Method for controlling security function execution with a flexible, extendable, and non-forgable block

ABSTRACT

A method, article, and system for providing an effective implementation of data structures, and application programming interface (API) functions that allow secure execution of functions behind a secure boundary. The controlling mechanism is a flexible, extendable, and non-forgeable block that details how values and parameters behind the secure boundary can be changed. The invention allows for one entity to execute a security function that will normally require extensive authorizations or dual or multiple control. The method and system comprise instructions that are cryptographically protected against alteration or misuse, wherein the instructions further comprise a trusted block that defines security policies that are permitted when an application program employs the trusted block in APIs. The trusted block has a number of fields containing rules that provide an ability to limit how the trusted block is used, thereby reducing the risk of the trusted block being employed in unintended ways.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to commonly assigned U.S. patent application Ser. No. 11/534,232, entitled METHOD FOR IMPROVED KEY MANAGEMENT FOR ATMS AND OTHER REMOTE DEVICES, filed on Sep. 22, 2006. This application is incorporated by reference herein in its entirety.

TRADEMARKS

IBM® is a registered trademark of International Business Machines Corporation, Armonk, N.Y., U.S.A. Other names used herein may be registered trademarks, trademarks or product names of International Business Machines Corporation or other companies.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to securely controlling critical values or parameters behind a secure boundary. The controlling mechanism is a flexible, extendable, and non-forgeable block that details how values and parameters behind the secure boundary can be changed. The invention allows for one entity to execute a security function that will normally require extensive authorizations or dual or multiple control. In particular the invention provides a method, article, and system for the effective implementation for securely transferring symmetric encryption keys to remote devices, such as Automated Teller Machines (ATMs), PIN entry devices, and point of sale terminals. It may also be used to exchange symmetric keys with another cryptographic system of any type, such as a Host Security Module (HSM) in a computer server.

2. Description of the Related Art

Role based access control systems are used in computer operating systems and in numerous computer software products. The role based access control system is favored in many applications because of its efficiency in daily administration of user authorizations. In such a system an administrative role is required in order to maintain all other roles. The number of users that can hold the administrative role is usually reduced to a smaller group of people in an organization. This works well in daily operations, but in certain situations (such as emergencies) a user will require additional authorizations. Since administrators cannot be expected to be available at all times, this is usually handled by granting these authorizations permanently or by special user accounts with very broad authorizations that can be used in these situations. Neither of these approaches is attractive from a security perspective.

Automated Teller Machines (ATMs), PIN entry devices, and point of sale terminals have become a central feature of modern life and have become quite prevalent in and out of the work environment. For example, during the course of the day, a user may utilize an ATM to conduct financial transactions, purchase gas for an automobile from a point of sale terminal in the form of a fuel pump via a credit or debit card, and purchase food at the grocery store in a checkout line with a point of sale terminal also with a credit or debit card. In all these instances, security is a prime concern, and an individual's data (card number, passwords, account numbers, etc.) must be kept secure and out of reach from unintended parties. In addition, access to controls and machine settings must be secured. The securing of sensitive data is normally accomplished through the use of encryption or encoding of the data. Encrypted data is only supposed to be accessible to an intended party with use of an encryption key to decipher the encoded information. The widespread use of electronic transaction processing applications has increased the demands for improved features, ease of use, and improved security.

Remote Key Loading refers to the process of exchanging symmetric encryption keys with a remotely located device, such as an ATM, from a central administrative site. The process encompasses two phases of key distribution:

-   -   1. Distribution of initial key encrypting keys (KEKs) to a newly         installed device. A KEK is a type of symmetric encryption key         that is used to encrypt other keys so they can be securely         transmitted over unprotected paths.     -   2. Distribution of operational keys or replacement KEKs,         enciphered under a KEK currently installed in the device.

A new ATM, when it is delivered from the manufacturer and being put into operation, has none of the affiliated bank's or service provider's security keys pre-installed. The process of getting the first key securely loaded in the ATM is a difficult one. Loading the first KEK into each ATM manually, in multiple cleartext key parts has typically been the security key loading process. In this process, two separate people must carry key part values to the ATM, and load them manually. Once inside the ATM, they are combined to form the actual KEK. In this manner, neither of the two people has the entire key, protecting the key value from disclosure or misuse. This method is labor-intensive and error-prone, making it expensive for the banks or service providers.

When an ATM is in operation, the bank or service provider can install new keys as needed by sending them enciphered under a KEK it installed at an earlier time. This is straightforward in concept, but the cryptographic architecture in the ATMs is often different from that of the host system sending the keys, and it is difficult to export the keys in a form understood by the ATM. For example, cryptographic architectures often enforce key usage restrictions, in which a key is bound to data describing limitations on how it can be used. The encoding of these restrictions and the method used to bind them to the key itself differs among cryptographic architectures, and it is often necessary to translate the format to that understood by the target device before a key can be transmitted. It is difficult to do this without reducing security in the system by making it possible to arbitrarily change key usage restrictions. The reduction in the level of security could potentially introduce holes that could permit misuse of the key management functions to attack the system.

The present invention is directed to addressing, or at least reducing the effects of, one or more of the problems set forth above, through the introduction of a new secure data structure called a trusted block. This disclosure describes a new and novel method for providing the necessary cryptographic functions to create and manage the special key forms needed for remote key distribution of this type. The invention described here also provides a mechanism through which the system owner can securely control these translations, preventing the majority of attacks that could be mounted by modifying usage restrictions.

GLOSSARY

-   Access Control—A mechanism for regulating access to resources, data     or services based on the role and identity of individual users. -   AND—When capitalized in this fashion, refers to the “AND” boolean     operation. -   API Function—Application programming interface is the interface that     a computer system, library, or application provides in order to     allow requests for services to be made of it by other computer     programs, and/or to allow data to be exchanged between them. -   BER encoding—Basic Encoding Rules for ASN.1 (Abstract Syntax     Notation One, defined in the X.208 standard). ASN.1 is a flexible     notation that allows one to define a variety of data types, from     simple types such as integers and bit strings to structured types     such as sets and sequences, as well as complex types defined in     terms of others. BER describes how to represent or encode values of     each ASN.1 type as a string of eight-bit octets. -   CBC—Cipher Block Chaining mode of encryption. -   CCA—The Common Cryptographic Architecture, a cryptographic     architecture and related APIs developed by IBM and used in many IBM     cryptographic products. -   CCA token—A key structure used to carry CCA keys in various formats.     The token can be either an internal token or an external token as     defined below. -   Cleartext—The form of a message or data that is transferred or     stored without cryptographic protection. -   Confounder—A bit string that is used to initialize the     encryption-block chaining value so that the encrypted result is     different each time a data value is encrypted. -   Control vector, or CV—That portion of a CCA key token that describes     how the key may be used. This information is defined in published     IBM documentation: IBM PCI Cryptographic Coprocessor CCA Basic     Services Reference and Guide. -   CVG—The Control Vector Generate service. This service generates a CV     based on a key type. -   DES—Data Encryption Standard—DES works by encrypting groups of 64     message bits, which is the same as 16 hexadecimal digits. To do the     encryption, DES uses “keys” where are also apparently 16 hexadecimal     digits long, or apparently 64 bits long. However, every 8th key bit     is ignored in the DES algorithm, so that the effective key size is     56 bits. But, in any case, 64 bits (16 hexadecimal digits) is the     round number upon which DES is organized -   Double length CV—A control vector that is 16 bytes in length. -   Double length Key—A DES key that is 16 bytes in length. -   DSV service—The Digital Signature Verify service. This service     performs a digital signature verification using the public key found     within the trusted block. -   EDE—Encrypt, Decrypt, Encrypt. This describes a method of     implementing Triple DES. -   Exporter key—A type of transport key, which is used to wrap a key     that will be used at a different node. -   External key—A key that is for exchange with another cryptographic     device. This key is encrypted with a transport key, also called a     key-encrypting key (KEK). The KEK is shared with the other device to     which the key may be transmitted. -   IMP—PKA—A limited authority importer KEK (key encrypting key) used     to protect PKA (public-key algorithm) structures when they are in     external form. -   Importer key—A type of transport key, which is used to unwrap a key     that will be used at a node. -   Input block—A trusted block token, which gets updated during the     trusted block creation process. -   Internal key—A key that is for use on the local cryptographic     device. This key is encrypted with a master key associated with the     cryptographic device. -   IV—Initial vector. This is a value used in CBC mode encryption. -   Key encrypting key (KEK)—A symmetric key that is used to encrypt a     key for transport to another device. Both devices must have the same     KEK key value so that one can encrypt a key with it, and the other     can decrypt the key after it is received. Also called a Transport     key. -   Keyword—An option that will direct the specific processing of a     process or routine. -   KVP—A Key Verification Pattern. This is a     cryptographically-calculated hash of a key's cleartext value, which     can be used to verify that the correct key value is used, without     disclosing any information about any bits of the key itself. -   Label—A string which can be used to reference a key token that has     been stored in a file or other repository. -   MAC—A Message Authentication Code. This is a     cryptographically-computed checksum, which uses a cryptographic key     to produce a fixed-length hash of a variable-length message string.     The MAC will change if any portion of the message is changed, or if     the wrong key is used. -   MAC key—A key designated for the purpose of computing a MAC (Message     Authentication Code). -   Master key—A key stored in a secure cryptographic device for the     purpose of encrypting keys to be used in that device which are     stored externally in unprotected storage. -   MDC-2—The 2-encryption per stage version of the Modification     Detection Code hashing algorithm discussed in the CCA Basic Services     Reference and Guide (available from IBM Corporation, Armonk, N.Y.,     and at www.ibm.com/security/cryptocards). -   MKVP—Master key verification pattern. -   PKA Master Key—Public Key Algorithm master key—a master key used to     encrypt keys for public-key algorithms such as RSA. -   PKCS 1.0—Digital Signature Hash Block 1 Formatting Method described     in the PKCS #1 v2.0 standard at website:     www.rsasecurity.com/rsalabs/pkcs. -   PKCS 1.1—Digital Signature Hash Block 0 Formatting Method described     in the PKCS #1 v2.0 standard at website:     www.rsasecurity.com/rsalabs/pkcs. -   PKCS 1.2—A method of formatting keys described in the PKCS #1 v2.0     standard at website: www.rsasecurity.com/rsalabs/pkcs. -   PKI service—The Public Key Import service. This service converts an     RSA key or trusted block from external form to internal form. The     PKI service is used to implement the Trusted Block Import service. -   RKX service—The Remote Key Export service is a method of secured     transport of DES keys from a security module (e.g. the 4764     Cryptographic Coprocessor) to a remote device, e.g. Automated Teller     Machine or vise versa, using asymmetric or symmetric techniques. The     DES keys to be transported are either key encrypting keys that are     generated within the 4764, or alternately, operational keys or     replacement KEKs enciphered under a KEK currently installed in a     remote device. This service accepts as input parameters: a public     key certificate, a transport key, a rule ID to identify the     appropriate rule section to be used within a trusted block, an     importer key, a source key, optional extra data that can be used as     part of the OAEP key wrapping process, and key check parameters that     are required to calculate the key check value. This service outputs     a symmetric encrypted key, an optional asymmetric encrypted key, and     an optional key check value. -   RKX token, or RKX key token—A data structure used to encase a key     that is generated, imported, or exported by the RKX service. The RKX     token contains: a length field indicating the size of the data it     contains, an 8 byte confounder, an encrypted key that is either 8,     16, or 24 bytes in size, a rule ID identifying the trusted block     rule that was used to create the RKX token, and a MAC value. The MAC     value is an ISO-16609 TDES CBC mode MAC that is computed over the     RKX token starting at offset zero in the token and including all     fields up to but not including the MAC value field itself. -   RSA OAEP—A method of formatting a key for secure transport described     in the PKCS #1 v2.0 standard at website:     www.rsasecurity.com/rsalabs/pkcs. -   Single Length Key—A DES key that is 8 bytes in length. -   Single Length CV—A control vector that is 8 bytes in length -   TBC service—Trusted Block Create service. This service creates a     trusted block in external form under dual or multiple control. -   TDES—Triple DES -   Triple DES—A mode of the DES encryption algorithm in which each     block of data is encrypted three times with either two or three     different eight-byte keys in order to provide increased security. -   TLV—Acronym for “Tag Length Value”. This refers to a data structure     design in which there exists: a tag field identifying the data     structure as a particular type; a length field of the entire     structure including the tag, length, and value fields; and a value     field which may be any number of bytes long. -   Token—A data structure representing a series of bytes that are to be     treated as an entity. The structure can contain cryptographic key     material, control vectors or other data related to the key. -   Transport key—See Key encrypting key. -   Triple Length Key—A DES key that is 24 bytes in length. -   Trusted Block—A data structure protected by a MAC that typically     contains an RSA public key and optional information (rules) to     control export of other keys associated with the device(s) that use     that public key. For remote key distribution, the public key will be     the root certification key for the remote device vendor, and it will     be used to verify the signature on public key certificates for     individual remote devices. In this case, the Trusted Block will also     contain Rules that will be used to generate or export DES keys for     the ATM or other remote devices. It is also possible for the Trusted     Block to be used simply as a trusted public key container, and in     this case the Public Key in the block will be used in CCA functions     such as Digital Signature Verify. In summary, the trusted block is a     data structure formatted to contain (1) zero or one trusted public     key section, (2) zero or more rule sections, (3) zero or one trusted     block label section, (4) one trusted block information section,     and (5) zero or one application defined data section. -   Variant—A value used to modify a key value. The variant is generally     a binary string of the same length as the key, and it is     exclusive-ORed with the key value to produce a variant key that is     used for some cryptographic operation. -   XOR—This refers to the “exclusive OR” Boolean operation.

SUMMARY OF THE INVENTION

Embodiments of the present invention include a data structure comprising instructions that are cryptographically protected against alteration or misuse. The instructions further comprise a trusted block that defines specific key management policies that are permitted when an application employs the trusted block to generate, import, or export symmetric cryptographic keys. The applications comprise: application programming interfaces (API); embedded firmware; operating system code; and hardware configured operations. The applications further comprise: a Trusted_Block_Create (TBC) function, and a Remote_Key_Export (RKX) function. The TBC function creates the trusted block, and the RKX function uses the trusted block to generate, import or export symmetric keys according to a set of parameters in the trusted block. The RKX function creates a RKX token, and the RKX token encases the keys.

The trusted block has zero or more fields containing rules that provide an ability to limit how the trusted block is used, thereby reducing the risk of the trusted block being employed in unintended ways or with unintended keys. The rules are created and approved by a cryptographic module under the control of at least two separate individuals. The rules are protected and bound to the trusted block. A rule comprises at least one of the following: an indictor of whether said rule is to be used to generate, import, or export the symmetric cryptographic keys; and an indicator of whether the generated, imported, or exported symmetric cryptographic keys should be in the form of a key that is immediately usable, or in the form of a RKX token that can only be used as a subsequent input to another RKX function call; or an indicator of whether the generated or said exported symmetric cryptographic key should be encrypted under a public key contained in a vendor-supplied certificate. The rules may also comprise a rule ID, which is a value that identifies the rule and where the rule should be used, and wherein the rules can reference other rules by referring to the rule ID. A rule may comprise at least one of the following: a transport key rule reference to identify what rule must have been used previously to produce a key used as a transport key input to the RKX function; and a source key rule reference to identify what rule must have been used previously to produce a key used as a source key input to the RKX function; or an importer key rule reference to identify what rule must have been used previously to produce a key used an importer key input to the RKX function.

In addition, the rules may comprise at least one of the following: information that controls the length of the keys that can be generated with a rule; and information controlling the length of keys that can be exported with a rule; or information controlling the length of keys that can be exported with a rule.

Rules may also comprise a plurality of variants; and wherein a first variant can be exclusive-or'ed (XORed) with the cleartext value of an output key exported by the trusted block prior to an output key being enciphered by a transport key; and wherein a second variant can be XORed with a transport key prior to a transport key being employed to encrypt the output key that is exported or generated by the trusted block.

A rule may also comprise a plurality of key label templates. The templates specify acceptable key label values for either keys that are to be exported by the trusted block, or importer keys that are to be used for decrypting keys that are to be imported by the trusted block. Host-applied labels are compared to the template; and the key will not be exported if the host-applied label does not correspond to the key label values specified by the template.

The keys of the present invention have structure. The key structure further comprises a token. The token is a data structure used to encase the keys. The token further comprises control vectors, while the rules comprise information to control which of the keys can be exported, based on the control vectors associated with the keys. In addition, the control vectors have values, wherein the rule information allows the acceptable control vectors to be specified so that sets of related control vector values are acceptable, while values outside of the set are rejected.

The data structure of the present invention further comprises activation and expiration date information, and the RKX function enforces said activation and expiration date information before carrying out instructions in the trusted block.

The rules of the present invention may also comprise a plurality of masks of control vector bits, where the rules comprise the required values of the control vector bits. The masks of the control vector bits and their required values are enforced by the RKX function when exporting a key or using an importer key. The rule may also comprise a control vector that is applied to a cryptographic module's master key, before the master key is being employed to encrypt an output key that is imported by the trusted block.

The trusted block of the present invention may optionally have a cryptographic public key. The TBC function creates and approves said cryptographic public key with the cryptographic module under the control of at least two separate individuals.

The RKX token of the present invention further comprises a confounder used to initialize an encryption-block chaining value during the encryption of an encased key. The confounder and the encased key within the RKX token are encrypted using the same MAC key that was used to protect the trusted block.

The RKX token further comprises a rule identification field that specifies a particular rule section that was used to create the RKX token. The RKX token further comprises a MAC value, and the MAC value is computed over the RKX token. The RKX token further comprises: an encrypted confounder; a key value; and a rule identification field that has a value. The rule identification field value can be compared with instructions within the rule sections of the trusted block, to determine whether the key within the RKX token may be used as either an importer key—key encrypting key, a source key, or exporter key-encrypting key.

Embodiments of the present invention also include a method for securely transferring symmetric cryptographic keys to remote devices. The method utilizes a data structure comprising instructions that are cryptographically protected against alteration or misuse. The instructions further comprise a trusted block that defines specific key management policies that are permitted when an application program employs the trusted block in application programming interface (API) functions to generate, import, or export symmetric cryptographic keys.

A system for implementing the method of the present invention, as well as, an article comprising one or more non-transitory machine-readable storage media containing instructions that when executed enable a processor to carry out the method, are also provided.

Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features, refer to the description and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a block diagram illustrating a MAC key encrypted in CBC mode.

FIG. 2 is a block diagram depicting a conceptual view of the RKX key structure according to an embodiment of the present invention.

FIGS. 3A and 3B are flow charts depicting the creation of the inactive, external trusted block according to an embodiment of the present invention.

FIGS. 4A and 4B are flow charts depicting the creation of the active, external trusted block according to an embodiment of the present invention.

FIGS. 5A and 5B are flow charts depicting the conversion of the active, external trusted block to internal trusted block format according to an embodiment of the present invention.

FIG. 6 is a flow chart depicting the steps of the main routine of the Remote Key Export methodology according to an embodiment of the present invention.

FIG. 7 is a flow chart depicting the steps of a validation routine that verifies the validity of the trusted block according to an embodiment of the present invention.

FIG. 8 is a flow chart depicting the routine for the decryption of the trusted block MAC key according to an embodiment of the present invention.

FIG. 9 is a flow chart depicting the routine for computing the MAC over a trusted block according to an embodiment of the present invention.

FIG. 10 is a flow chart depicting the routine for verifying that the transporter key is either a valid RKX token or a valid CCA token according to an embodiment of the present invention.

FIG. 11 is a flow chart depicting the routine for verifying that the importer key is a valid internal CCA token according to an embodiment of the present invention.

FIG. 12 is a flow chart depicting the routine for verifying that source key is a valid RKX token or a valid CCA token according to an embodiment of the present invention.

FIG. 13 is a flow chart depicting the routine for verifying the validity of the certificate parameters length field as well as the validity of the lengths contained within the certificate parameters table according to an embodiment of the present invention.

FIG. 14 is a flow chart depicting the routine for generating an RKX token data structure according to an embodiment of the present invention.

FIG. 15 is a flow chart depicting the routine for exporting either an RKX data structure or CCA data structure according to an embodiment of the present invention.

FIG. 16 is a flow chart depicting the application programming interface used to carry out digital signature verification according to an embodiment of the present invention.

The detailed description explains the preferred embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The trusted block concept provides a great deal of flexibility and power, but at the same time it gives the security administrators the ability to tightly control what can be done with the cryptographic keys used by their applications. The new methods define new procedures for distributing and loading these keys using public key cryptographic techniques, which allow banks or other service providers to load the initial KEKs without sending anyone to the ATMs, or to exchange keys with other types of cryptographic systems. These methods will make the process quicker, more reliable, and much less expensive for the banks or other service providers. This disclosure describes a new and novel method for providing the necessary cryptographic functions to create and manage the special key forms needed for remote key distribution of this type. The invention described also provide a mechanism through which the system owner can securely control these translations, preventing the majority of attacks that could be mounted by modifying usage restrictions. An example of a cryptographic coprocessor used with server systems that would implement the present invention is the IBM 4764, which is also known as the PCIXCC or the Crypto Express2 (CEX2).

The trusted block is the central data structure to support all remote key loading functions. The trusted block provides great power and flexibility, but this means that it must be designed and used with care in order to have a secure system. The required security is provided through several features of the design.

-   -   Dual control (multiple control) is used to create a trusted         block. Two separate individuals must cooperate in order to         create a usable block.     -   The trusted block includes cryptographic protection that         prevents any modification after it is created.     -   A number of fields in the trusted block rules offer the ability         to limit how the block is used, reducing the risk of using it in         unintended ways or with unintended keys.         Two API functions are defined to manage and use trusted blocks.         The function Trusted_Block_Create (TBC) will create a Trusted         Block, and the function Remote_Key_Export (RKX) will use a         trusted block to generate or export symmetric keys according to         the parameters in the trusted block. In general all         implementations of this invention, as well as for purposes other         than cryptographic key management, must employ two functions         similar to TBC and RKX, namely     -   One that encapsulates the security policy using a dual (or more)         control mechanism, and     -   One that executes the security function.

Table 1 provides an overview of the structure of the trusted block.

TABLE 1 Structure version information Public key Modulus Exponent Attributes Trusted Block Protection MAC key Information MAC Flags KVP Activation/Expiration dates Trusted Block name/label Label (optional) Rules Rule 1 Rule 2 Rule 3 . . . Rule N Application defined data Data defined and understood only by the application using the trusted block

The elements of table 1 are as follows:

-   Public Key This contains the public key and its attributes. For     distribution of keys to a remote device, this will be the root     certification key for the device vendor, and it will be used to     verify the signature on public-key certificates for specific     individual devices. In this case, the trusted block will also     contain Rules that will be used to generate or export symmetric keys     for the device. It is also possible for the trusted block to be used     simply as a trusted public key container, and in this case the     Public Key in the block will be used in general-purpose     cryptographic functions such as digital signature verification. The     public key attributes will contain information on key usage     restrictions. -   Protection Info This section contains information that is used to     protect the trusted block contents against modification. A CBC-mode     MAC (Please note that alternative keyed hash algorithms, for example     HMAC, can be used in place of the MAC without altering the intent of     the invention) is calculated over the trusted block using a     randomly-generated symmetric key, and the MAC key itself is     encrypted and embedded in the block. For the internal form of the     block, the MAC key is encrypted with a variant of the device master     key. For the external form, the MAC key is encrypted with a fixed     variant of a key-encrypting key. The KVP field contains the KVP for     the master key that was used, and is filled with binary zeroes if     the trusted block is in external format. The flags field contains     the following Boolean flags.     -   The Active flag indicates whether the trusted block is complete         and ready for use. This is the basis for enforcing dual control         over creation of the block. One person creates the block, but in         an inactive state. Subsequently, a second person approves the         block and causes the Active flag to be turned on.     -   The date checking flag indicates whether the cryptographic         device should check the expiration and activation dates for the         trusted block. If this flag is off, date checking must be         performed outside of the device if it is required. This is done         so that the trusted block can be used with devices that have         their own internal clock, as well as with devices that do not. -   Trusted Block name/label This field optionally contains a text     string that is a key label (name) for the trusted block. It is     included in the block for use by an external system such as a host     computer, and not by the card itself.     -   It is possible to disable use of trusted blocks that have been         compromised or need to be removed from use for other reasons by         publishing a revocation list containing the key names for the         blocks that must not be used. A host computer system could check         each trusted block before it is used in the cryptographic         device, to ensure that the name from that block is not in the         revocation list. -   Expiration date and Activation date The trusted block can optionally     contain an expiration date and an activation date. The activation     date is the first day on which the block can be used, and the     expiration date is the last day when the block can be used. If these     dates are present, the date checking flag in the trusted block will     indicate whether the cryptographic device should check the dates     using its internal clock. If the device does not have its own clock,     a host computer system application program can check the activation     and expiration dates before the trusted block is used by the device.     This is not quite as secure, but it is still valuable, and storing     the dates in the block itself is preferable to making the     application store it somewhere else and maintain the association     between the separate trusted block and activation and expiration     dates. -   Rules A variable number of rules can be included in the block. Each     rule contains information on how to generate or export a symmetric     key, including values for variants to be used in order to provide     keys in the formats expected by systems with differing cryptographic     architectures. Rules are described in detail later in this document. -   Application-defined data An optional field that an application     program can use to include its own data in the trusted block. The     cryptographic module does not use or examine this data in any way,     but it is carried in the trusted block and protected in the same way     as the other contents of the block.

The “Trust” in the Trusted Block is established by creating the block under dual control. Once that trust has been established, it is ensured using cryptographic techniques. The trusted block does not contain any data that has to be kept secret, but it is essential that its contents be protected against unintended modification. In order to accomplish this, the block is protected using a MAC, calculated using a symmetric key. The MAC key is randomly generated when the MAC is first calculated on the trusted block.

The MAC is calculated in the following way, for a trusted block B.

1. Make a temporary copy of the trusted block B. Call this temporary copy T.

2. Fill the following fields in block T with binary zeroes.

-   -   The MAC value.     -   The MAC key.     -   The KVP.

3. Calculate the MAC over the entire block T using the MAC key.

4. Insert the MAC into the MAC field of the trusted block B.

The MAC key itself is encrypted and embedded in the trusted block. If the trusted block is in internal form, the MAC key is encrypted with a variant of the device master key. If the block is in external form, it is encrypted using a key-encrypting key. In either case, the MAC key is prepended with a randomly generated confounder, which is equal to the block length of the encryption algorithm (For DES or Triple-DES the confounder is eight bytes in length) before it is encrypted. Encryption is in CBC mode, however alternative encryption modes will also work without altering the intent of the invention. ECB mode is not acceptable, however; encryption must use a mode that chains successive blocks of text so that each encryption depends on the content of the current message block and the preceding blocks. FIG. 1 illustrates the MAC key 100 encrypted in the CBC mode. The MAC key has two parts the confounder 102, and the key 104 itself.

For an internal format trusted block, the string shown in FIG. 1 is encrypted in CBC mode using a variant of the master key, with a zero IV (initialization vector). The variant is a fixed, randomly generated string of bytes with length equal to the master key. If the master key is a DES or Triple-DES key, each byte of the variant must have even parity so that the parity of the resulting key is not altered (Keys used with DES algorithms have odd parity in each byte of the key, so the variant must be constructed so that the resulting key after applying the variant still has odd parity in each byte.) The KVP for the device master key is stored in the KVP field of the trusted block so that availability of the correct master key can be verified when the block is used. For an external format trusted block, the string is encrypted in CBC mode using a provided key-encrypting key. Before it is used to encrypt the MAC key, the KEK is XORed with a variant in order to ensure the key cannot be misused in other CCA services. The variant value is a fixed, randomly generated value equal in length to the KEK. Like the variant for the master key described above, each byte of this variant must have even parity if it is used with a DES or Triple-DES key so that it does not affect the parity of the key.

The Trusted Block can have one or more rules, which define how symmetric keys will be generated, imported, or exported under control of the block. These are generally the keys that will be shared with the remote device, such as an ATM. As a part of the Trusted Block, the rules are created and approved by the cryptographic device owner under dual control, and protected from modification.

The IBM CCA cryptographic architecture uses control vectors exclusive-ORed with its symmetric keys, but most non-CCA cryptographic devices use variants, or use no modifying value at all. An important feature of the rules is the ability to specify arbitrary values to be XORed with the key being generated or exported. For additional flexibility, a second value can be specified to be XORed with the KEK used to wrap the key being generated or exported. For yet more flexibility, a third value can be specified to be XORed with the key being imported by the importer KEK. These values can be CCA control vectors, variants, or zero. This gives complete flexibility in sending keys to different types of cryptographic systems.

The Trusted Block rules can contain the following values to control key generation, import, and export.

-   Rule ID A character string identifying the rule. When a program uses     a Trusted Block, it provides a rule ID as an input parameter. This     indicates which rule should be used, since the Trusted Block can     have more than one rule. In addition, rules can reference other     rules, and they do this by using the rule ID. (see next item.) -   Transport key rule reference, Importer key rule reference, and     Source key rule reference Rules can be used together. A key can be     generated using one rule from the trusted block, and then used as     input in a subsequent call. The rule references allow a rule to     specify what other rule must have been used to produce a key used as     input on this call. There are two different references that can be     specified, and both are optional in a rule.     -   The transport key rule reference indicates what rule must have         been used to produce the key used in the transport_key input to         the RKX function, which is described later. If the reference is         present in the rule, the transport key must be an RKX token,         which contains the ID of the rule used to produce that token.         The rule ID in the input RKX token must be equal to the ID         specified in the rule.     -   The import key rule reference indicates what rule must have been         used to produce the key used in the importer_key input to the         RKX function, which is described later. If the reference is         present in the rule, the import key must be an RKX token, which         contains the ID of the rule used to produce that token. The rule         ID in the input RKX token must be equal to the ID specified in         the rule.     -   The source key rule reference indicates what rule must have been         used to produce the key used in the source_key input to the RKX         function. If the reference is present in the rule, the source         key must be an RKX token, which contains the ID of the rule used         to produce that token. The rule ID in the input RKX token must         be equal to the ID specified in the rule.     -   Note: the character * (asterisk) may be used in some         implementations as a wildcard character in rule ID references.         This would allow a reference to match multiple rules. -   Generate/Import/Export indicator A rule can be used to generate new     symmetric keys, to import a key, or to export existing keys. This     flag indicates which of the three this rule is for. -   Symmetric Encrypted Output Form This indicates the form of the     encrypted output key. The form can either be a key immediately     usable in cryptographic functions, or an RKX token that is bound to     the Trusted Block and can only be used as input to a later call to     the RKX function. This value will implicitly indicate the encryption     method, for example CBC or ECB mode. -   Asymmetric Encrypted Output Format/PKA Output Form This indicates     what format should be used when encrypting the generated or exported     key under the public key supplied within the public key certificate     that is input to the RKX function. Examples are the     industry-standard PKCS1.2 format or RSA OAEP format. -   Generated key length The length of a generated key. Output key     length is unused for export of existing keys, since that length is     defined by the size of the key being exported. -   Source key length limits This specifies the range of key lengths     that are acceptable for export using this rule. -   Output key variant A variant (which may have the value of a CCA     Control Vector) to be XORed with the cleartext value of the output     key, before it is enciphered. This can be any bit string, with     length greater than or equal to the length of the key itself. If the     variant is longer than the key, the leftmost bytes of the variant     are used up to the length of the key. -   KEK variant A variant (which may have the value of a CCA Control     Vector) to be XORed with the KEK that is used to wrap the generated     or exported key, before that KEK is used to wrap the key. -   Key Label Template The host can optionally provide the key label     (name) of a key being exported, or of a key being used as the     importer KEK. The rule can optionally contain a key label template,     which will be matched against the host-supplied key label, using     wildcards so that the template can match a set of related key     labels. If the supplied label does not match the template in the     rule, the cryptographic device will reject the request with an     error. -   Import key CV restrictions—This field only applies when the importer     KEK is a CCA key which has an associated control vector (CV). It     will not be used for importer KEKs that are RKX tokens.     -   Two fields work together to restrict the acceptable control         vectors for CCA keys to be used as importer KEKs. By limiting         the key types that can be used as importers, misuse of the         import operation can be greatly reduced.     -   One field contains a mask to indicate which CV bits should be         checked. The second field contains the required values for those         CV bits that are to be checked. The CV for the key to be used as         an importer is first ANDed with the mask, and then the result is         compared with the required values. If the two do not match, the         request is rejected with an error. -   Export key CV restrictions This field only applies when the key     being exported is a CCA key, which has an associated control vector     (CV). It will not be used for systems that do not use CCA keys.     -   Two fields work together to restrict the acceptable control         vectors for CCA keys to be exported. By limiting the key types         that can be exported, misuse of the export operation can be         greatly reduced.     -   One field contains a mask to indicate which CV bits should be         checked. The second field contains the required values for those         CV bits that are to be checked. The CV for the key to be         exported is first ANDed with the mask, and then the result is         compared with the required values. If the two do not match, the         request is rejected with an error. -   Transport key CV values—There are two transport key CV values which     may be used. One transport key CV may be applied to the transport     key KEK before it is used to export the generated or exported key.     The other transport key CV may be applied to the key being imported. -   Key check algorithm Some applications will require a key check value     for the key being generated or exported. An output parameter is     provided to return the check value, and this field of the rule can     be used to indicate what key check algorithm is to be used. The     calculation of the key check value is optional. Note that an input     parameter is also provided for use when the key check algorithm     requires input parameters, such as a nonce, ATM ID, or other value.

Table 2 provides information on the content of the Trusted Block structure, including the rules it can contain.

TABLE 2 Section Optional? Description Trusted Yes This includes the public key itself. Please note public key that the Trusted Block contains cryptographic information that guarantees the integrity of this public key and binds it to the local system. A rule Yes A trusted block may have zero or more rules sections. If no rules are present, the block is simply a trusted public key. If there are rules, each is uniquely identified by its rule ID, and the block can be used by the RKX function to generate or export symmetric keys. Trusted Yes This value can be used to identify the trusted block label block. One example of its use is for a host access control system such as RACF to verify that the application has the authority to use the trusted block identified by this label. Trusted No This section contains control and security block information related to the Trusted Block. It is information separated from the public key and other sections, because this section is mandatory while the others are optional. Application- Yes This section can be used to include application- defined data defined data in the Trusted Block. The data is not examined or used in any way by the CCA code, but it is cryptographically bound to the block so it can be trusted.

The trusted public key section (Table 2) contains the public key modulus, exponent, and key usage flags to control how the key can be used. Table 3 summarizes the features and example applications of the public key. It should be noted that the public key is not a required part of a trusted block. In some applications, trusted blocks are used only in relation to symmetric key based key management, and in those cases the Trusted Block may not contain a public key section.

TABLE 3 Trusted Public Key Section contents Public key exponent, e. Modulus, n. Key usage flags These flags indicate how the public key can be used. Examples include restrictions that would permit the key to be used as follows: Use the key only in digital signature operations. Use the key only in key management operations. Use the key in both digital signature and key management operations. These are only examples. Other key usage restrictions could also be defined.

The Trusted Block information section (Table 2) contains control and security related to the trusted block. It is required in all Trusted Blocks as indicated by its non-optional status. Table 4 summarizes the Trusted Block information section.

TABLE 4 Trusted block information Activation status. This status can have one of the two following values. INACTIVE Trusted block is Inactive and will not be accepted for any purpose other than activation with the TBC function. ACTIVE Trusted block is Active and can be used in CCA functions such as RKX, TBC, and DSV. Trusted block information objects. This is a variable-length series of data objects for the trusted block information section. They are described below. Most are optional and are only present if needed.

The following objects (Table 4) contain optional parts of the trusted block information section. If used, the objects are included in the structure shown above.

The protection information object (Table 5) is required, and contains the data used to secure the trusted block. By making this a separate object, the opportunity to replace the protection mechanism in the future; for example, with a different MAC or HMAC algorithm is preserved.

TABLE 5 Protection information object Encrypted MAC key. This includes the encryption of both the confounder and the key. MAC KVP for the device master key. This is set to binary zeroes if the trusted block is in external format.

The activation and expiration dates object (Table 6) is optional, and contains activation and expiration dates for the trusted block. It also contains a flag to indicate whether the cryptographic device should check the dates before using the block.

TABLE 6 Activation and expiration date object CHECK-DATE - a Boolean flag indicating whether the cryptographic device should check the activation and expiration dates before using the trusted block. Activation date for the trusted block. Expiration date for the trusted block.

The Trusted Block label section (Tables 2 and 7) is optional and contains a label to identify the Trusted Block.

TABLE 7 Trusted block label Label

The application-defined data section (Tables 2 and 8) is optional, and contains arbitrary data defined by the application program that creates the trusted block. It is not examined or used in any way by the device, but is bound to the trusted block by the MAC and can be used by the application program. An example is the use of this section to hold a public-key certificate for the trusted public key. The data is variable-length, but it must not cause the entire trusted block to exceed its maximum allowable size.

TABLE 8 Application-defined data Length of application-defined data - values can be 0-400, inclusive. Application-defined data

The rule section (tables 2 and 9) of the Trusted Block is used to define a rule for key generation or export. The trusted block can have zero or more rules sections, where each section defines a different rule. Each rule has an embedded name that is used to identify it, so that a selected rule can be used when the trusted block is passed to the RKX function. The rules section consists of a set of fixed fields, followed by a variable number of optional objects. The optional objects are concatenated at the end of the fixed portion of the section structure, and only those objects that are needed are included in the structure. Table 9 summarizes the key features of the rule section.

TABLE 9 Rule Rule ID. A character string value identifying the rule. The Rule ID for this rule must be different from the ID used in any other rules in this trusted block. Generate/Import/Export flag. This Boolean flag indicates whether the rule is for generation of a new symmetric key, for import of a key, or for export of an existing key. Generated key length. This specifies the length, in bytes, of the key to be generated if this rule is for generation. If the rule is for key export, this value must be zero. Key check algorithm identifier. This value identifies an algorithm to be used to compute a check value on the key. Examples include the following. Do not compute a key check value. Encrypt a block of binary zeroes with the key. Compute a hash of the key using the SHA-1 algorithm. Compute a hash of the key using the MDC-2 algorithm. These are only examples, and other options are also possible. Symmetric-encrypted output key format This is used to specify the format of the output key, which is either encrypted under the transport key in a CCA token or in an RKX token. The following formats are defined.  The generated key is output in an RKX token.  The exported key is output in an external key token, encrypted by the  transport key identified by the transport_key_identifier parameter to  RKX. A transport key variant (see Transport Key Variant TLV)  and/or a CCA Control Vector (see Common Export Key Parameters)  may be applied to the transport key. If both are applied, the variant is  applied first, and then the CV.  The imported key is output in an internal key token, encrypted by the  symmetric master key. An output key variant (see Common Import  Key Parameters) may be applied to the cleartext imported key, and/or  a CCA Control Vector (see Common Import Key Parameters) may be  applied to the master key prior to encryption. Other formats are also possible. Asymmetric-encrypted output key format This is used to specify the format of the output key which is encrypted under the RSA key provided as input to the RKX function. The following formats are defined.  Do not output an asymmetric-encrypted copy of the key. The  asymmetric-encrypted key length parameter of RKX will be set to  zero on output.  The key is output in PKCS 1.2 format.  The key is output in RSAOEAP format. This format can make use of  Extra Data, and that data can be provided in a parameter that is part of  the RKX API. Other formats are also possible. Objects for optional fields. This is a series of zero or more objects. The objects are defined below.

The following objects contain optional parts of the trusted block rule section. If used, the objects are concatenated to the end of the base rule section structure defined above. The objects can appear in any order.

The transport key variant object is optional. It is used to hold a variant, which is XORed into the cleartext value of the transport key before that key is used to encrypt the key RKX is generating or exporting. The length must be greater than or equal to the length of the transport key that is supplied to RKX when this rule is used. If the variant is longer than the transport key, it is truncated on the right to the length of the key before it is used. Please note that if the transport key is in an RKX token, the variant is XORed with only the key itself, and not with the confounder that precedes the key in the token.

The transport key rule reference object is optional. If present, it contains the rule ID of the rule that must have been used to create the transport key being used to encrypt the key being generated or exported. This reference can only be used if the transport key is provided in an RKX token, which contains the rule ID for the rule used to create that key.

The common export key parameter object is required when exporting a key, and is optional when generating or importing a key. It holds the parameters that are used to process the key being exported. This includes:

-   -   The variant which is XORed into the cleartext value of the key         being exported, or generated before that key is encrypted.     -   The minimum and maximum length allowed for the key to be         exported. Note that this is the actual key length, not the         length of the structure that carries the key.     -   Flags to indicate options.         The length of the variant can be greater than the length of the         key it is applied to. If the key to be exported is shorter than         the variant, the variant is truncated on the right to be the         same length as the key, and the truncated value is then used         with the key. For example, if the variant length is 24 and the         key being exported is only 16 bytes, then only the leftmost 16         bytes of the variant are used. The remaining 8 bytes are         ignored. Table 10 summarizes common export parameters object.

TABLE 10 Common Export Key Parameters object Flags (reserved) Export key minimum length, in bytes. (For example, 8 for a single-length DES key) Export key maximum length, in bytes Output key variant length, in bytes. Output key variant. This is applied to the cleartext value of the key being exported or generated. Transport key CV length, in bytes. Transport key CV, to be applied to the transport key before using it to export the key.

The source key rule reference object is optional, and is used to hold a rule reference for a source key that is provided to the RKX function in the form of an RKX token. That token contains the name of the rule that was used to create the token, and the source key rule reference, if present, is compared with that value in the RKX token. If the two do not match, execution of RKX aborts and an error is returned. The export key CCA token parameters object is optional and is only used if the export key parameter is in the form of a CCA token. It is ignored (if present) when the export key is provided as an RKX token. The object contains fields that are compared with values in the CCA token, or associated with that token. Table 11A summarizes characteristics that the source key must match.

TABLE 11A Export key CCA token parameters object Flags (reserved) Export key CV limit mask. Export key CV limit template. Source key label template..

The Source key label template is a template that can be matched against the key label for the source key, when that key is specified using a key label. If the actual label for the key does not match the template (which can contain wildcards), the request is rejected. The CV limit mask and CV limit template have the same length, which is the length defined in the field Export key maximum length.

The import key CCA token parameters object is optional and is only used if the import key parameter is in the form of a CCA token. It is ignored (if present) when the import key is provided as an RKX token. The object contains fields that are compared with values in the CCA token, or associated with that token. Table 11B summarizes characteristics that the import key must match.

TABLE 11B Import key CCA token parameters object Flags (reserved) Import key CV limit mask Import key CV limit template. Import key label template..

The Import key label template is a template that can be matched against the key label for the import key, when that key is specified using a key label. If the actual label for the key does not match the template (which can contain wildcards), the request is rejected. The CV limit mask and CV limit template have the same length, which is the length defined in the field Import key maximum length.

The common import key parameter object is required when importing a key, but it is not used when generating or exporting a key. It holds the parameters that are used to process the key being imported (the supplied key in the source_key parameter). This includes:

-   -   The variant which is XORed into the cleartext value of the key         being imported, before that key is encrypted.     -   The minimum and maximum length allowed for the key to be         imported. Note that this is the actual key length, not the         length of the structure that carries the key.     -   Flags to indicate options.         The length of the variant can be greater than the length of the         key it is applied to. If the key to be imported is shorter than         the variant, the variant is truncated on the right to be the         same length as the key, and the truncated value is then used         with the key. For example, if the variant length is 24 and the         key being exported is only 16 bytes, then only the leftmost 16         bytes of the variant are used. The remaining 8 bytes are         ignored. Table 11C summarizes common import parameters object.

TABLE 11C Common Import Key Parameters object Flags (reserved) Import key minimum length, in bytes. (For example, 8 for a single-length DES key) Import key maximum length, in bytes Output key variant length, in bytes. Output key variant. This is applied to the cleartext value of the key being imported. Transport key CV length, in bytes. Transport key CV, control vector for the key being imported.

The following API functions support the creation of Trusted Blocks, and generation and export of keys using those blocks. In the presentation of the API functions below, the following terminology is used to describe option values passed to the functions.

-   Rule Array—The rule array is a variable-length array of 8-character     text strings, each of which contains a keyword defining an option to     be passed to the API function. The length of the array is determined     by the number of options that are to be passed to the function, and     it may vary for different invocations of the same function when     different processing options are used. -   Rule Array Count—The rule array count parameter specifies the number     of 8-character option keywords that are contained in the rule array.     Please note that alternative methods can be used to pass options to     an API function. The rule array is just used as the method in this     description of the operations of these functions.

The Trusted Block create (TBC) function is used to create a Trusted Block under dual control. The block will be in external form, encrypted under a transport key (KEK). The format of the TBC function is shown in table 12.

TABLE 12 TBC (  return_code Output  rule_array_count Input  rule_array Input  input_block_length Input  input_block Input  transport_key_identifier Input  trusted_block_length In/Output  trusted_block) Output input_block_length This parameter contains the length of the value in the input_block parameter, in bytes. input_block This parameter contains the complete trusted block structure, which will be updated by the function and returned in parameter trusted_block. The length of the input_block string is indicated by parameter input_block_length. Its content is dependent on the rule array keywords supplied to the function. When the option keyword INACTIVE is given, the block is complete. It includes all fields of the trusted block structure, but typically does not have the MAC protection. If MAC protection is not present, the MAC key and MAC value will be filled in by the function. If the MAC protection is present due to recycling of an existing trusted block, then the MAC key and MAC value will be overlaid with the new MAC key and MAC value by this function. The Active flag will be set to False (0) in the block returned in trusted_block. When the option keyword ACTIVATE is given, the block is complete, including the MAC protection which is validated during execution of the function. The Active flag must be in the False (0) state. On output, the Active flag will be changed to the True (1) state, and the MAC value will be recalculated using the same MAC key. transport_key_identifier This contains a key label (identifying name) or key token for a key encrypting key that is used to protect the trusted block. trusted_block_length This parameter contains the length of the value in parameter trusted_block, in bytes. trusted_block This is a buffer provided by the caller for the trusted block constructed by the function. On input, its length in parameter trusted_block_length contains the size of the buffer. On output, the length parameter is updated with the actual byte length of the trusted block written to the buffer. The trusted block consists of the data supplied in parameter input_block, but with the MAC protection and Active flag updated according to the rule array keyword that is provided. See table 13 and the description of the rule array keywords below for details on the actions.

TABLE 13 Keyword Meaning Operation (one required) INACTIVE Create the trusted block, but in inactive form. The MAC key is randomly generated, encrypted with the transport key, and inserted into the block. The Active flag is set to False (0), and the MAC is calculated over the block and inserted in the appropriate field. The resulting block is fully formed and protected, but it is not usable in any other CCA services. Use of the INACTIVE keyword is authorized by the access control system separately from the ACTIVATE operation. ACTIVATE Activate the supplied trusted block by turning on the Active flag and then recalculating the MAC using the key that is already present in the block. This makes the trusted block usable in CCA services. Use of the ACTIVATE keyword is authorized by the access control system separately from the INACTIVE operation.

Either INACTIVE or ACTIVATE must be supplied to indicate the action. The two options are authorized separately, so that they can be assigned to different people. The same person should not be authorized to execute both the INACTIVE and ACTIVATE operations.

For keyword INACTIVE, the trusted block is constructed and protected with the MAC. The following steps summarize the INACTIVE operation.

-   1. Verify that the user is authorized to perform the INACTIVE     operation of this function. Abort with an error if not authorized. -   2. Validate the trusted block structure in parameter input_block.     Abort with an error if the trusted block is not valid. -   3. Validate the key in parameter transport_key_identifier. The     definition of a valid key will depend on the particular     implementation, but it would generally include validation that the     data is not corrupt, and does not contain any invalid values. -   4. Verify that there is enough space in the output buffer by     verifying that parameter trusted_block_length is greater than or     equal to parameter input_block_length. -   5. Copy the block in parameter input_block to the buffer in     parameter trusted_block and set parameter trusted_block length to     the value of parameter input_block_length. -   6. Set the Active flag in trusted_block to False. -   7. Randomly generate a new symmetric key to be used in computing the     MAC for the trusted block. -   8. Compute the MAC over the trusted block contents, using the key     generated in step 7. Use an IV of binary zeroes. Insert the MAC into     the MAC field of trusted_block. -   9. Generate a random confounder with length equal to the symmetric     algorithm block length, and encrypt the confounder concatenated with     the MAC key from step 7 under the key provided in parameter     transport_key_identifier. The MAC key should be encrypted in CBC     mode using an IV of binary zeroes. Insert the encrypted MAC key in     the appropriate field of trusted_block.

For keyword ACTIVATE, the trusted block is validated, and the Active flag is set so that the block can be used in other cryptographic services. The following steps summarize the operation.

-   1. Verify that the user is authorized to perform the ACTIVATE     operation of this function. Abort with an error if not authorized. -   2. Validate the key in parameter transport_key_identifier. The     definition of a valid key will depend on the particular     implementation, but it would generally include validation that the     data is not corrupt, and does not contain any invalid values. -   3. Validate the trusted block received in parameter input_block. -   4. Verify that there is enough space in the output buffer by     verifying that parameter trusted_block_length is greater than or     equal to parameter input_block_length. -   5. Copy the block in parameter input_block to the buffer in     parameter trusted_block and set parameter trusted_block_length to     the value of parameter input_block_length. -   6. Parse the trusted block from parameter trusted_block to obtain     the enciphered MAC key and the MAC. -   7. Recover the cleartext version of the MAC key that is in the     trusted block, by decrypting it with the transport key from     parameter transport_key_identifier and removing the 8-byte     confounder -   8. Compute the MAC over the block in trusted_block, using the key     recovered in step 7. Use an IV of binary zeroes. Compare the     computed MAC to the MAC value parsed from the trusted block in     step 6. If they are not equal, exit with an error. -   9. Set the Active flag to True in the block in parameter     trusted_block. -   10. Compute a MAC over the block in parameter trusted_block, using     the key recovered in step 7. Use an IV of binary zeroes. Please note     that the MAC value will be different from the one received with the     input trusted block, since the Active flag has been modified.

The remote key export (RKX) function uses the trusted block to generate, import, or export symmetric keys for local use and for distribution to and from an ATM or other remote device. The application program indicates what rule in the trusted block is to be used. The function can either generate a new key, import an existing key, or export an existing key. The specified rule is examined to determine whether a generate, import, or export operation is to be performed.

The RKX function uses a special structure to hold encrypted symmetric keys in a way that binds them to the trusted block, and allows sequences of RKX calls to be bound together as if they were an atomic operation. Incorporating the following three features into the RKX key structure does this.

-   -   The key is enciphered using a variant of the MAC key that is in         the trusted block. A fixed, randomly derived variant designated         for this purpose is applied to the MAC key before it is used.         The variant has the same length as the MAC key. If the MAC key         is a DES or Triple-DES key, the variant will have even parity on         each byte, so it will not affect the parity of the key it is         applied to. The enciphered key is protected against disclosure,         since the trusted block MAC key is itself protected at all         times.     -   The structure includes the rule ID for the trusted block rule         that was used to create the key. A subsequent call to RKX can         use this key with a trusted block rule that references the rule         ID that must have been used to create this key, and that can be         compared with this value.     -   A MAC is computed over the encrypted key and the rule ID, using         the same MAC key that is used to protect the trusted block         itself. This MAC guarantees that the key and the rule ID cannot         be modified without detection, providing integrity and binding         the rule ID to the key itself. In addition, the MAC will only         verify with the same trusted block that created the key, thus         binding the key structure to that specific trusted block.

FIG. 2 shows a conceptual view of the RKX key structure, which is also known as an RKX token. The detailed structure for this key token will vary for different implementations. The RKX key is enciphered with a confounder, in a manner similar to that described previously for the MAC key.

The format of the RKX is shown in table 14.

TABLE 14 RKX ( return_code Output rule_array_count Input rule_array Input trusted_block_length Input trusted_block Input certificate_length Input certificate Input certificate_parms_length Input certificate_parms Input transport_key_length Input transport_key Input rule_id_length Input rule_id Input Importer_key_length Input Importer_key Input source_key_length Input source_key Input asym_encrypted_key_length Input/Output asym_encrypted_key Output sym_encrypted_key_length Input/Output sym_encrypted_key Output extra_data_length Input extra_data Input key_check_parameters_length Input key_check_parameters Input key_check_length Input/Output key_check_value ) Output

The description of the RKX parameters are as follows:

-   rule_array_count The number of 8-character elements in the     rule_array parameter. The value must be zero for this function. -   rule_array An array of 8-character keywords. Each keyword is     left-justified and padded on the right with space characters. There     are no rule array keywords for this function. -   trusted_block_length This parameter contains the length of the     trusted_block parameter, in bytes. -   trusted_block This is a string containing the trusted block used to     validate the public key certificate, and defining the rules for key     generation, import, and export. The trusted block must be in     internal form. -   certificate_length This is the length of the string in parameter     certificate, in bytes. If the certificate length is zero, the     function will not attempt to use or validate the certificate in any     way. This means that output parameter asym_encrypted_key_length will     contain zero, and parameter asym_encrypted_key will not be changed     from its content on input. -   certificate This is a string containing a public-key certificate.     The certificate must contain the public key modulus and exponent in     binary form, as well as a digital signature. The signature will be     verified using the root public key that is in the trusted block     supplied in the trusted_block parameter. -   certificate_parms_length This is the length of the certificate     parameters in certificate_parms, in bytes. The length must be of     sufficient size to accommodate the locations and lengths of values     within the certificate in parameter certificate if a certificate is     supplied, as indicated by certificate_length having a value greater     than zero. If certificate_length is zero, then both     certificate_parms_length and certificate_parms are ignored. -   certificate_parms This string is a structure identifying the     location and length of values within the certificate in parameter     certificate. It is the responsibility of the calling application     program to provide these values. This method gives the greatest     flexibility to support different certificate formats.     -   The information in this structure includes a value indicating         the hash algorithm used to compute the digital signature. It         could also include information on the public-key algorithm used         for the signature. -   transport_key_length The length of the string in the transport_key     parameter, in bytes. -   transport_key The transport key is a Key Encrypting Key (KEK) that     is used to encrypt a key generated or exported by the RKX function     when that key is in the form of a CCA token. For the generation     operation, the transport key encrypts the newly generated key. For     the export operation, it encrypts the exported version of the key     received in parameter source_key. -   rule_id_length This parameter contains the length of the string in     parameter rule_id, in bytes. -   rule_id The trusted block can contain multiple rules, each of which     is identified by a rule ID value. This parameter contains a string     specifying the rule in the trusted block that will be used to     control key generation, import, or export. -   Importer_key_length This parameter contains the length of the string     in parameter importer_key, in bytes. It must be zero if the     operation is generate, not import or export. -   Importer_key This parameter contains a RKX token, a CCA key token or     key label for the IMPORTER key-encrypting key that is used to     decipher the key passed in parameter source_key. It is unused if RKX     is being used to generate a key, and not to import or export one. -   source_key_length This parameter contains the length of the string     in parameter source_key, in bytes. It must be zero if the operation     is generate, not export. Note that this is the length of the entire     structure passed in parameter source_key, not the length of the key     itself inside that structure. -   source_key This parameter contains a key to be exported. It must be     empty (source_key_length=0) if the operation is generate. The key     can be either an operational key in a form understood by the     cryptographic device, or an RKX key structure. -   asym_encrypted_key_length On input, this parameter contains the     length of the application program's buffer provided with parameter     asym_encrypted_key. On output, that value is replaced with the     length of the key returned in that parameter. -   asym_encrypted_key This parameter is the buffer RKX uses to return a     generated or imported, exported key that is encrypted under the     public (asymmetric) key passed in parameter certificate. An error     will be returned if the caller's buffer is too small to hold the     value that would be returned. -   sym_encrypted_key_length On input, this parameter contains the     length of the application program's buffer provided with parameter     sym_encrypted_key. On output, that value is replaced with the length     of the key returned in that parameter. -   sym_encrypted_key This parameter is the buffer RKX uses to return a     generated, imported, or exported key. This key may be either an RKX     token or a CCA token that is encrypted under the key-encrypting key     passed in parameter transport_key. This key may also be an internal     CCA token if the RKX service performs an import operation. An error     will be returned if the caller's buffer is too small to hold the     value that would be returned. -   extra_data_length This parameter contains the length of the string     passed in parameter extra_data, in bytes. -   extra_data This parameter is optional, and is used to pass extra     data that can be used as part of the OAEP key wrapping process. It     is only applicable when the output format for the RSA-encrypted key     returned in asym_encrypted_key is RSA OAEP. Note that this format is     specified as part of the rule in the trusted block. -   key_check_parameters_length This parameter contains the length of     the key check parameters that are provided as input in parameter     key_check_parameters. It must be zero if no parameters are used by     the key check algorithm specified in the rule. -   key_check_parameters This parameter contains parameters that are     required to calculate a key check value, which will be returned in     parameter key_check_value. The parameters that are required will     depend on the key check algorithm that is specified, and most     algorithms will not require any parameters at all. -   key_check_length On input, this parameter contains the length of the     application program's buffer provided with parameter     key_check_value. On output, that value is replaced with the length     of the key check value that the function writes to the     key_check_value buffer. -   key_check_value This parameter is the buffer RKX uses to return a     key check value that it calculates on the generated or exported key.     Values in the rule specified with parameter rule_id can specify a     key check algorithm that should be used to calculate this output     value.

It should be noted that the RKX rule could contain a source key label template, which is matched against the key label for the source_key parameter if that key is specified using a label. Since the host CCA software replaces a label with the actual key token read from the key storage file, the label must be passed to the cryptographic module in another way. The host CCA API software for the RKX function accomplishes this. If the application program passes the source_key parameter as a key label, the RKX API code includes that label in the request parameter block that is sent to the cryptographic module. In this way, the device receives both the key token itself, and the key label that can be matched against the template in the rule. Using an identical technique, an import key label template can be matched against the key label for the importer key parameter if that key is specified using a label.

The generate, import, and export operations all begin with the following steps:

-   -   1. Validate all input parameters, including the trusted block         structure. Abort with an error if any are invalid.     -   2. Verify that the Active flag in the trusted block is set to         True. If not, this trusted block is not yet ready for use and         must be rejected with an error.     -   3. If the trusted block contains expiration/activation dates AND         the date checking flag in the block indicates the dates should         be validated by the cryptographic module, verify that the         current device internal clock shows a date that is less than or         equal to the expiration date contained in the trusted block, and         is greater than or equal to the activation date.     -   4. Verify that the trusted block is in internal form. Exit with         an error if not.     -   5. Extract the encrypted MAC key from the trusted block and         recover its cleartext value by decrypting with a fixed variant         of the device master key.     -   6. Use the MAC key to verify the MAC on the trusted block         contents. Exit with an error if the MAC fails to verify.     -   7. If parameter certificate_length is not zero, use the public         key in the trusted block to verify the digital signature         embedded in that certificate. The necessary certificate objects         are located with information from the certificate_parms         parameter. If the signature does not verify, exit with an error.     -   8. Locate the rule in the trusted block with an ID equal to the         value in parameter rule_id. If a matching rule cannot be found         in the block, abort with an error. If the rule is found,         validate the contents of the rule. Each element of the rule must         be a valid element, and the value associated with each rule         element must be valid.         The generate, import, and export operations have different         processing beyond these common steps. That processing follows         these steps, at a high level.

The generate operation comprises the following steps:

-   -   1. Verify that no parameters or rule elements referring to a         source key are present, since there is no source key with the         generate operation.         -   Verify that parameters source_key_length and             importer_key_length are zero     -   2. If the rule contains a transport key rule ID reference, then         do the following.         -   Verify that the transport_key parameter contains an RKX             token.         -   Verify that the rule ID in the transport_key parameter is             equal to the transport key rule ID reference in the rule             being used.     -   3. Verify that the generated key length in the rule is less than         or equal to the length of the output key variant in the rule.     -   4. If the output is specified to be a CCA key token, verify that         the length of the transport key variant in the rule is greater         than or equal to the length of the key received in the         transport_key parameter.     -   5. Generate a random value for the output key. Call this         value K. The length of K must be equal to the output key length         contained in the rule. Ensure that key K is not a DES weak or         semi-weak key.     -   6. If the output key format is to be a CCA token, recover the         clear value of the transport key received in the transport_key         parameter. The format is determined by examining the version         number field of the key token. If this key is in an RKX token,         this step includes verifying the MAC that is part of the token.     -   7. If the output key format is to be a CCA token and the rule         contains a transport key variant, XOR that variant with the         clear transport key value recovered in the previous step.     -   8. If the rule specifies a key check algorithm, calculate the         key check value according to the specified algorithm.     -   9. XOR the output key variant from the rule into the         randomly-generated key K from above. Adjust the resulting key to         have valid DES key parity.     -   10. Encrypt the key from step 9, in the mode specified in the         output key format element of the rule.         -   If the format is a CCA key token, encrypt using the             transport key from step 6.         -   If the format is an RKX token, this will include building             the token with the encrypted key and the ID of the rule             being used to generate it, and calculating the MAC over             these two values. The key is then encrypted using a variant             of the trusted block MAC key.         -   Verify that the length of the resulting encrypted key             structure is less than or equal to the value in parameter             sym_encrypted_key_length. If it is, copy the key token to             the buffer indicated in parameter sym_encrypted_key, and set             parameter sym_encrypted_key length to the length of this             token.     -   11. If a public key certificate was provided to the RKX function         in parameter certificate, and if the rule specifies that an         asymmetric-encrypted output key should be produced, then encrypt         the key from step 9 using the public key from the certificate.         The form can be either PKCS1.2 or RSA OAEP (Note that other         formats may be used without altering the intent of the         invention). Verify that the length of the resulting encrypted         key is less than or equal to the value in parameter         asym_encrypted_key_length. If it is, copy the encrypted key to         the buffer indicated in parameter asym_encrypted_key, and set         parameter asym_encrypted_key_length to the length of this token.     -   12. If the rule contains a key check algorithm specifier,         calculate the key check value according to the specified         algorithm. For some algorithms, this may involve use of input         parameters contained in key_check_parameters. Verify that the         caller's output buffer size, indicated by parameter         key_check_length, is large enough to hold the calculated key         check value. If so, copy the value to that buffer and put the         length of the key check value in parameter key_check_length.

The import operation comprises the following steps:

-   -   1. Verify that the transport_key parameter is null     -   2. If the rule contains an import key rule ID reference, then do         the following.         -   Verify that the import_key parameter contains an RKX token.         -   Verify that the rule ID in the import_key parameter is equal             to the import key rule ID reference in the rule being used.     -   3. Verify that the length of the import key variant in the rule         is greater than or equal to the length of the key received in         the import_key parameter.     -   4. If the parameter importer_key_length is 64 (verify this         length is 64 only when the source key is a CCA token. If the         source key is an RKX token, the importer_key_length and         importer_key parameters are ignored) then verify that the         import_key parameter contains a CCA key token     -   5. Recover the importer_key into the clear and then do the         following         -   If the importer key was provided as an RKX token, the             recovery includes verifying the MAC that is part of the             token.         -   Verify that the length is between the minimum and maximum             key lengths         -   Apply the variant to the recovered importer_key.     -   6. Verify that the source key parameter is a CCA token and         recover the clear value of the source key received in the         source_key parameter by decrypting it with the key passed in         parameter importer_key_identifier. Call this recovered key K.     -   7. Verify that the length of K is between the minimum and         maximum export key length values contained in the rule. Also         verify that this is the less than or equal to the length of the         output key variant in the rule.     -   8. If the rule specifies a key check algorithm, calculate the         key check value on the key K according to the specified         algorithm.     -   9. If the rule contains an output key variant, XOR that variant         into the cleartext source key K from above. Adjust the resulting         key to have valid DES key parity.         -   Verify that the output format is CCA and encrypt the key             from step 9 by the master key, using the mode specified in             the output key format element of the rule.         -   Verify that the length of the resulting key token is less             than or equal to the value in parameter             sym_encrypted_key_length. If it is, copy the key token to             the buffer indicated in parameter sym_encrypted_key, and set             parameter sym_encrypted_key_length to the length of this             token.

The export operation comprises the following steps:

-   -   1. If the rule contains a transport key rule ID reference, then         do the following.         -   Verify that the transport_key parameter contains an RKX             token.         -   Verify that the rule ID in the transport_key parameter is             equal to the transport key rule ID reference in the rule             being used.     -   2. Verify that the length of the transport key variant in the         rule is greater than or equal to the length of the key received         in the transport_key parameter.     -   3. Verify that parameter importer_key_length is 64 (Verify this         length is 64 only when the source key is a CCA token. If the         source key is an RKX token, the importer_key_length and the         importer_key parameters are ignored.), the length of a CCA key         token.     -   4. If the source key parameter is a CCA token, recover the clear         value of the source key received in the source_key parameter by         decrypting it with the key passed in parameter         importer_key_identifier. If the source key is in an RKX token,         the recovery step includes verifying the MAC that is part of the         token, then decrypting the key with the MAC key stored in the         trusted block. The format is determined by examining the version         field in the key token. Call this recovered key K.     -   5. Verify that the length of K is between the minimum and         maximum export key length values contained in the rule. Also         verify that this is the less than or equal to the length of the         output key variant in the rule.     -   6. Recover the clear value of the transport key received in the         transport_key parameter. The format of the key is determined by         examining the key token. If this key is in an RKX token, the         recovery step includes verifying the MAC that is part of the         token.     -   7. If the rule contains a transport key variant, XOR that         variant with the clear transport key value recovered in the         previous step.     -   8. If the rule specifies a key check algorithm, calculate the         key check value according to the specified algorithm.     -   9. If the rule contains an output key variant, XOR that variant         into the cleartext source key K from above. Adjust the resulting         key to have valid DES key parity.     -   10. Encrypt the key from step 9, using the mode specified in the         output key format element of the rule.         -   If the format is an RKX token, the key from step 9 is             encrypted using a variant of the trusted block MAC Key. The             RKX token is built using the encrypted key and the ID of the             rule used to export it, and calculating the MAC over the RKX             token from offset 0 up to but not including the MAC value             field of the RKX token. If the format is a CCA key token,             encrypt using the transport key from step 6, or from step 7,             if the transport key variant was applied.         -   Verify that the length of the resulting key token is less             than or equal to the value in parameter             sym_encrypted_key_length. If it is, copy the key token to             the buffer indicated in parameter sym_encrypted_key, and set             parameter sym_encrypted_key_length to the length of this             token.     -   11. If a public key certificate was provided to the RKX function         in parameter certificate, and if the rule specifies that an         asymmetric-encrypted output key should be produced, then encrypt         the key from step 9 using the public key from the certificate.         The form will can be PKCS1.2 or RSA OAEP (Note that other         formats may be used without altering the intent of the         invention). Verify that the length of the resulting encrypted         key is less than or equal to the value in parameter         asym_encrypted_key_length. If it is, copy the encrypted key to         the buffer indicated in parameter asym_encrypted_key, and set         parameter asym_encrypted_key_length to the length of this token.     -   12. If the rule contains a key check algorithm specifier,         calculate the key check value according to the specified         algorithm. For some algorithms, this may involve use of input         parameters contained in key_check_parameters. Verify that the         caller's output buffer size, indicated by parameter         key_check_length, is large enough to hold the calculated key         check value. If so, copy the value to that buffer and put the         length of the key check value in parameter key_check_length.

Additional API functions must be provided in order to have a workable system. Many cryptographic systems will already have functions that could be enhanced to provide the specific operations described below.

The Trusted Block Import function is used to import trusted blocks, which are created in external form, but must be in internal form when used.

For the purpose of importing a trusted block, the parameters will be as follows:

-   source_key will contain the trusted block in external form, as     produced by the Trusted_Block_Create function. -   transport_key will contain the KEK that was used in     Trusted_Block_Create to protect the trusted block MAC key. -   target_key will receive the internal form of the trusted block, in     which the MAC key is enciphered under the proper variant of the     device master key instead of the KEK.

The Trusted Block Import function operates as follows:

-   1. Parse the trusted block from parameter source_key to obtain the     enciphered MAC key and the MAC. -   2. Recover the cleartext version of the MAC key that is in the     trusted block, by decrypting it with the proper variant of the     transport key from parameter transport_key. -   3. Compute the MAC over the trusted block using the key recovered in     step 2. Compare the computed MAC to the MAC value parsed from the     trusted block in step 1. If they are not equal, exit with an error. -   4. Verify that the Active flag is set to True in the trusted block.     If not, exit with an error. -   5. Encipher the MAC key recovered in step 2, using the proper     variant of the device master key. Encipher the key in CBC mode with     an IV of binary zeroes. Insert the enciphered MAC key in the trusted     block, replacing the one in the input block, which was enciphered     with the transport key. -   6. Copy the device master key KVP into the protection information     section of the trusted block. -   7. Return the updated trusted block structure to the caller.

A digital signature verification function (DSV) must be able to verify digital signatures using public keys that are contained in trusted blocks. The DSV could do this with any trusted block, regardless of whether the block also contains rules to govern its use when generating or exporting keys with the RKX function.

The parameters will be as follows:

-   public_key will contain the public key to be used in verifying the     signature. This can be a trusted block, but if the DSV function is     implemented to be general in nature it may also be possible for this     to be a public key in other forms. -   hash will contain the hash of the message string to be verified. -   signature will contain the digital signature that is to be verified.

The DSV function will operate as follows:

-   -   1. Parse the trusted block from parameter public_key to obtain         the public key value.     -   2. Decrypt the signature value and extract the hash from the         decrypted result.     -   3. Compare the hash parameter with the hash recovered in step 2.         If the two are equal, indicate that the signature was verified.         If not, indicate that the signature was not verified.

The reencipher Trusted Block function is used when the Trusted blocks are in internal form and use the device master key to encrypt the embedded MAC key. When the master key is changed, the Reencipher Trusted Block function must be able to reencipher this under the new master key so that the trusted blocks are still usable.

The parameters will be as follows:

-   trusted_block will contain the trusted block that is to be     reenciphered.

The reencipher Trusted Block function will operate as follows.

-   -   1. Verify that the trusted block is in internal form. Abort with         an error if it is not.     -   2. Decrypt the MAC key in the trusted block using the proper         variant of the old device master key.     -   3. Encipher the MAC key using the proper variant of the new         device master key, and insert this value into the trusted block,         replacing the version that was enciphered under the old master         key.     -   4. Insert the KVP for the new master key into the trusted block.

In a first preferred embodiment of the Remote Key Loading design, the Trusted Block create function will be described further with the creation of the Trusted Block under dual control. The Trusted Block is a data structure that typically contains an RSA public key and optional information (rules) to control export of other keys associated with the devices that use the public key. This structure is protected by an ISO-16609 CBC mode TDES Message Authentication Code (MAC). The trusted block will contain the rules that will be used to generate or export DES keys. The trusted block could also serve as a trusted public key container, and in this case the public key in the trusted block can be used in digital signature verification services. The first step in preparing a trusted block is to call the trusted block create routine.

The trusted block create (TBC) routine or service has three primary inputs: the input block, transport key and a keyword. The input block contains all the fields of a trusted block token but will be updated by this service to contain a valid MAC and MAC key. The transport key is the key encrypting key that is used to wrap or protect the trusted block. There are two valid keywords: INACTIVE and ACTIVATE. The keywords are options, which will direct the specific processing of the routine.

The first step in the Trusted Block creation is to call the TBC service specifying the INACTIVE keyword. This service call will produce an inactive, external trusted block token. The trusted block is fully formed and protected with a MAC at this point but, it is not usable by any other service. A second person with different authorization can then perform the second step. The result of step one is input to the second call to the trusted block create service along with the transport key and the ACTIVATE rule keyword. This call produces an external, active, trusted block token. The trusted block is now usable in other services. After activation, another service is called to put the trusted block into internal format. The public key import (PKI) service performs this operation. Note that the PKI service is used to implement the Trusted Block Import service. The next two tables will describe the application programmer's interfaces (API) for the trusted block create (TBC) and public key import (PKI) services. The charts that follow will describe the processing flow of each service.

The API outlined in Table 15 for the TBC service highlights the major input and output fields used by the preferred embodiment for this verb. The first column contains the API parameter name. The second column indicates whether the parameter is an input to or an output from the service. The third column indicates whether the item is an integer or a string.

TABLE 15 rule_array_count Input Integer rule_array Input String input_block_length Input Integer input_block_identifier Input String transport_key_identifier Input String trusted_block_length In/Output Integer trusted_block_identifer Output String

The parameters are as follows:

rule_array_count The rule_array_count parameter is a pointer to a string variable containing the number of elements in the rule_array variable. The value must be one.

-   rule_array The rule_array parameter is a pointer to a string     variable containing an array of keywords. The keywords are eight     bytes in length, must be left-justified and padded on the right with     space characters. The rule_array keywords are shown in table 16.

TABLE 16 Keyword (Operation) Meaning INACTIVE Create the trusted block, but in inactive form. The MAC key is randomly generated, encrypted with the transport key, and inserted into the block. The Active flag is set to False (0), and the MAC is calculated over the block and inserted in the appropriate field. The resulting block is fully formed and protected, but it is not usable in any other services. ACTIVATE Use of this keyword makes the trusted block usable in other services. The Active flag is set to True (1), and the MAC is calculated over the block and inserted in the appropriate field. The resulting block is fully formed and protected.

-   input_block_length The input_block_length parameter is a pointer to     an integer variable containing the number of bytes of data in the     input_block_identifier parameter. -   input_block_identifier The input_block_identifier parameter is a     pointer to a string variable containing a trusted block label or     complete trusted block token, which will be updated by the verb and     returned in parameter trusted_block_identifier. The length of the     input_block_identifier string is indicated by parameter     input_block_length. Its content is dependent on the rule array     keywords supplied to the verb.     -   When the keyword INACTIVE is given, the block is complete but         typically does not have the MAC protection. If the MAC         protection is present due to recycling of an existing trusted         block, then the MAC key and MAC value will be overlaid by the         new MAC key and MAC value. The input_block_identifier includes         all fields of the trusted block token, but the MAC key and MAC         will be filled in by the verb. The Active flag will be set to         False (0) in the block returned in trusted_block_identifier.     -   When the keyword ACTIVATE is given, the block is complete,         including the MAC protection which is validated during execution         of the verb. The Active flag must be in the False (0) state on         input. On output, the block will be returned in         trusted_block_identifier provided the identifier is a token. The         Active flag will have been changed to the True (1) state, and         the MAC value recalculated using the same MAC key. If the         trusted_block_identifier is a label, the updated block will be         written to a key storage repository such as a disk or other         means. -   transport_key_identifier The transport_key_identifier parameter is a     pointer to a string variable containing a key label or key token,     which has special usage restrictions, that is used to protect the     trusted block. The usage restrictions are indicated by the presence     of an IMP-PKA control vector in the transport key token. -   trusted_block_length The trusted_block_length parameter is a pointer     to an integer variable containing the number of bytes of data in the     trusted_block_identifier parameter. If the trusted block length is     not a multiple of 8 bytes, the code handling this API will pad the     trusted block with zero bytes up to the next multiple of 8 bytes so     that an ISO-16609 CBC mode triple DES MAC can be performed     successfully on the trusted block within the adapter. -   trusted_block_identifier The trusted_block_identifier parameter is a     pointer to a string variable containing a trusted block label or     trusted block token for the trusted block constructed by this API.     On input, its length in parameter trusted_block_length, contains the     size of the buffer. On output, the trusted_block_length parameter is     updated with the actual byte length of the trusted block written to     the buffer if the trusted_block_identifier is a token. The trusted     block consists of the data supplied in parameter     input_block_identifier, but with the MAC protection and Active flag     updated according to the rule array keyword that is provided.     -   If the trusted_block_identifier is a label identifying a key         record, the returned trusted block token will be written to a         key storage repository such as a disk or other means.

The API outlined in table 17 for the Trusted Block Import function highlights the major input and output fields used by the preferred embodiment. The first column contains the API parameter name. The second column indicates whether the parameter is an input to or an output from the service. The third column indicates whether the item is an integer or a string.

TABLE 17 rule_array_count Input Integer rule_array Input String Source_key_token_length Input Integer Source_key_token Input String transport_key_identifier Input String target_key_identifier_length In/Output Integer target_key_identifier In/Output String rule_array_count The rule_array_count parameter is a pointer to an integer variable containing the number of elements in the rule_array variable. The value must be zero for this verb. rule_array The rule_array parameter is a pointer to a string variable containing an array of keywords. The keywords are eight bytes in length, and must be left-justified and padded on the right with space characters. The rule_array parameter is not presently used in this service, but must be specified. source_key_token_length The source_key_token_length parameter is a pointer to an integer variable containing the number of bytes of data in the source_key_token variable. If the source_key_token parameter is an external Trusted Block key token which is not a multiple of 8 bytes, the code handling this API will pad the trusted block with zero bytes up to the next multiple of 8 bytes so that an ISO- 16609 CBC mode triple DES MAC can be performed successfully on the trusted block within the adapter. source_key_token The source_key_token parameter is a pointer to a string variable containing the trusted block in external form as produced by the Trusted Block Create (CSNDTBC) verb with the ACTIVATE keyword. This API will be used to encipher the MAC key within the trusted block under a fixed variant of the PKA master key instead of the transport key-encrypting key. The transport_key_identifier must contain a tranport KEK with special usage controls in this case. transport_key_identifier The transport_key_identifier parameter is a pointer to a string variable containing either a key-encrypting-key token, a key label of a key- encrypting-key token, or a null key-token. If the source key token is a trusted block, then this key must be a KEK with special usage controls. The usage restrictions are indicated by the presence of an IMP-PKA control vector in the transport key token. It will be used to decrypt the MAC key contained within the trusted Block in the source_key_token. target_key_identifier_length The target_key_identifier_length parameter is a pointer to an integer variable containing the number of bytes of data in the target_key_identifier variable. On output, and if the size is of sufficient length, the variable is updated with the actual length of the target_key_identifier variable. target_key_identifier The target_key_identifier parameter is a pointer to a string variable containing either a key label identifying a key record that is stored in a key storage repository such as a disk or other means; or is other information that will be overwritten with the imported key, such as a trusted block whose MAC key is now enciphered under the PKA master key.

The flowcharts (FIGS. 3A, 3B, 4A, 4B, 5A and 5B) outline the key steps required to create a trusted block under dual control and transform it into an operational entity.

Step 1 (FIGS. 3A and 3B) of the creation of the Trusted Block is as follows (Creation of the Inactive, External Trusted Block starting at 300 in FIG. 3A):

-   -   1. The first thing that must be done is to validate that the         caller of the service has authority to call the service with the         INACTIVE keyword (302). This is critical to ensure that an         unauthorized party is not trying to perform the first step in         creating a trusted block. If the credentials of the caller         cannot be verified against the authorization criteria, the         caller will not be allowed to perform the step, an error will be         posted and the process terminated (304).     -   2. Before beginning, verify that the necessary inputs have been         provided by the caller (306).     -   3. The input block must be validated (308). The validation         includes verifying that there are no extra sections, the token         internal or external indicator is set, and the fields have valid         lengths and values. These are the requirements for the input         block when the INACTIVE keyword is specified.     -   4. If the validation was not successful an error indicating the         nature of the problem should be returned to the caller (310,         312).     -   5. Start building the trusted block (314). The input block forms         the foundation for the trusted block that is being created. Copy         the important fields into the trusted block structure.     -   6. The transport key token must be validated (316). The token         itself is a wrapper for the key material. The token also         contains key usage information. It must be ensured that the key         wrapper has valid fields and usage control information. The         usage control information must be a special key encrypting key         that can be used in trusted block creation operations. The usage         restrictions are indicated by the presence of an IMP-PKA control         vector in the transport key token.     -   7. If the token structure itself fails consistency checking or         the wrong type of key usage information is present in the token,         it must be rejected and an appropriate error posted (318, 320).     -   8. The active flag in the trusted block must be set to the         inactive state (322). The active flag in the trusted block         indicates whether it can be used in other services or whether it         is only eligible to be used in the second step of the trusted         block creation process. By setting the flag to inactive, the         trusted block is then typically used in the second step of the         trusted block creation process; however, it may be reused in the         first step of the creation process.     -   9. The trusted blocks are always in the external state during         the creation phase. Since the trusted block will contain a MAC         key that is encrypted under a fixed variant of an IMP-PKA key         encrypting key, it is necessary to ensure that the indicator is         set to external (324).     -   10. The generation of random confounder whose length is equal to         the symmetric algorithm is required (326). The confounder will         be prepended to the MAC key later in the process.     -   11. Generation of a 24-byte random value, which will be used as         a TDES MAC key, is required (328). The key will be used to         create the MAC over the trusted block.     -   12. Compute an ISO-16609 CBC mode TDES MAC over the trusted         block and store the MAC in the appropriate field of the trusted         block (330). The MAC value protects both the trusted block's         integrity as well as its authenticity. It allows the detection         of any changes to the trusted block's contents.     -   13. The transport key will be used to encrypt the MAC key         concatenated with the confounder. The transport key should be         exclusive or'ed with a variant, which is a value the same size         as the key which will change the key's value (332). CBC mode         encryption should be used with an initialization vector of         binary zeros. Those skilled in security understand what CBC mode         encryption is and how initalization vectors are used.     -   14. Store the encrypted confounder/MAC key value in the         appropriate place in the trusted block (334).     -   15. Creation of the external, inactive trusted block has been         completed (336, 338). The newly formed trusted block and its         length could now be returned to the caller.

Step 2 (FIGS. 4A and 4B) of the creation of the Trusted Block is as follows (Creation of the Active, External Trusted Block starting at 400 in FIG. 4A and center on authorization, validation, and initialization):

-   -   1. The first thing that must be done is to validate that the         caller of the service has authority to call the service with the         ACTIVATE keyword (402). This is critical to ensure that an         unauthorized party is not trying to perform the second step in         creating a trusted block. If the credentials of the caller         cannot be verified against the authorization criteria, the         caller will not be allowed to perform the step, an error will be         posted and the process terminated (404).     -   2. Before beginning, verify that the necessary inputs have been         provided by the caller (406).     -   3. The input block must be validated (408). This time it must         contain an INACTIVE external trusted block. Validation includes         verifying that there are no extra sections, the token external         indicator is set, the active flag is disabled, and fields within         the block have valid lengths and values. These criteria must be         met when the ACTIVATE keyword has been specified.     -   4. If the validation was not successful an error indicating the         nature of the problem should be returned to the caller (410,         412).     -   5. Continue building the trusted block. The input block contains         the trusted block that was created in the first creation step.         Copy the important fields into the trusted block structure         (414).     -   6. The transport key token must be validated (416). The token         itself is a wrapper for the key material. The token also         contains key usage information. We must ensure that the key         wrapper has valid fields and usage control information. The         usage control information must be a special key encrypting key         that can be used in trusted block creation operations. The usage         restrictions are indicated by the presence of an IMP-PKA control         vector in the transport key token.     -   7. If the token structure itself fails consistency checking or         the wrong type of key usage information is present in the token,         it must be rejected and an appropriate error posted (418, 420).     -   8. Now we must recover the confounder and MAC key that are         stored in the trusted block. In the previous creation step, the         MAC key and confounder were encrypted with the transport key         exclusive or'ed with a variant. Once again this transport key         must be exclusive or'ed with a variant but this time used to         decrypt the confounder/MAC key value in the trusted block (422).     -   9. The MAC key must now be used to create an ISO-16609 CBC mode         TDES MAC over the trusted block (424).     -   10. The MAC value computed in step 24 must be compared with the         MAC value that is stored in the trusted block (426).     -   11. If the MAC values to not successfully compare, the trusted         block has been tampered with or the caller provided the wrong         transport key. If a verification failure occurs an error code         will be returned to the caller (428, 430).     -   12. If the verification of the trusted block was successful, the         Active flag in the trusted block can now be set to the active         state (432).     -   13. A MAC is once again computed over the trusted block and it         is inserted into the appropriate place in the trusted block         (434). This MAC value will be different than the one previously         stored in the trusted block because the Active flag has now been         set.     -   14. The creation of the active external trusted block is         complete (436, 438). It can now be used by other services.

Step 3 (FIGS. 5A and 5B) of the creation of the Trusted Block is as follows (Convert the Active, External Trusted Block to Internal Trusted Block Format starting at 500 in FIG. 5A—The public key import service (PKI) implements the Trusted Block Import function and is used to convert the trusted block form external format to internal format. When the trusted block is in internal format it is considered operational and can be used on the local system):

-   -   1. The first thing that must be done is to validate that the         caller of the service has authority to import a trusted block         (502). As with creation of the trusted block authorization is         required to use the trusted block in other services even if the         trusted block is in the active state. If the credentials of the         caller cannot be verified against the authorization criteria,         the caller will not be allowed to perform the step, an error         will be posted and the process terminated (504).     -   2. The trusted block must be validated (506). The trusted block         must be external and in the active state. Validation includes         verifying that there are no extra sections, the token external         indicator is set, the active flag is enabled, and fields within         the block have valid lengths and values.     -   3. If the validation was not successful an error indicating the         nature of the problem should be returned to the caller (508,         510).     -   4. The transport key token must be validated. The token itself         is a wrapper for the key material. The token also contains key         usage information. We must ensure that the key wrapper has valid         fields and usage control information (512). The usage control         information must indicate that this is a special key encrypting         key that can be used in operations on trusted blocks. The usage         restrictions are indicated by the presence of an IMP-PKA control         vector in the transport key token.     -   5. If the token structure itself fails consistency checking or         the wrong type of key usage information is present in the token,         it must be rejected and an appropriate error posted (514, 516).     -   6. The next step is to decrypt the confounder/MAC key value that         is in the trusted block. The transport key is exclusive or'ed         with a variant and the decryption operation is performed (518).     -   7. The MAC key must now be used to create a MAC over the trusted         block. The MAC is an ISO-16609 CBC mode TDES MAC (520).     -   8. The MAC value computed in step 520 must be compared with the         MAC value that is stored in the trusted block (522). If the MAC         values to not successfully compare, the trusted block has been         tampered with or the caller provided the wrong transport key. If         a verification failure occurs an error code will be returned to         the caller (524).     -   9. Change the trusted block token identifier from external to         internal (526).     -   10. An ISO-16609 CBC mode TDES MAC is once again computed over         the trusted block and it is inserted into the appropriate place         in the trusted block (528). This MAC value will be different         than the one previously stored in the trusted block because the         trusted block token identifier has been changed to internal.     -   11. Making the trusted block internal and ready for local use         means that the MAC key and confounder must be encrypted under a         fixed variant of the asymmetric master key. The asymmetric         master key is exclusive or'ed with a variant and the encryption         operation is performed (530).     -   12. Insert the encrypted MAC key and confounder into the         appropriate location in the trusted block. Associated with the         asymmetric master key is a master key verification pattern or         MKVP (532). The MKVP is a cryptographically-computed hash of a         key's cleartext value which can be used to verify that the         correct key value is used, without disclosing any information         about any bits in the key itself. The MVKP is also inserted into         the trusted block.     -   13. This completes the conversion of an external active trusted         block token to an internal active trusted block token (534,         536). The token can now be used by other services for local         operations.

A preferred embodiment of the present invention utilizes functions that use the trusted block to perform cryptographic operations. These functions include:

-   -   The Remote Key Export (RKX) function that is used to generate,         import, or export a key under control of a trusted block.     -   The Digital Signature Verify (DSV) function that is used to         verify an RSA digital signature using the public key carried in         a trusted block.

The Remote Key Loading method of a preferred embodiment of the present invention involves encipherment of a newly generated or preexisting key under a key encrypting key and optionally, under a public key. A group of services in the preferred embodiment accomplish the Remote Key Loading. The service directly responsible for the remote key loading methodology is known as the Remote Key Export (RKX) service. The Trusted Block Create (TBC) service creates a “trusted block” containing not only the rules governing how the Remote Key Export service is to operate, but also containing a trusted root public key used to verify the digital signature in a certificate which in turn contains a public key that is used ultimately for the encipherment of the newly generated or preexisting key.

Additional contents of the trusted block of a preferred embodiment of the present invention include a Message Authentication Code (MAC) key and MAC value. A MAC value is computed over the entire content of the trusted block except for the encrypted MAC key field, MAC value field, and master key verification pattern field of the trusted block. The trusted block is created in external form, meaning that the MAC key used to create the trusted block's MAC value is enciphered under a key encrypting key. Prior to use by the Remote Key Export service, the trusted block must be converted to internal form, meaning that the MAC key contained in the trusted block must be changed from being enciphered under a key encrypting key to being enciphered under a variant of the PKA (or asymmetric) master key. This trusted block conversion from external form to internal form is accomplished via the Public Key Import (PKI) service. In the preferred embodiment, the PKI service is used to implement the Trusted Block Import Function.

Using the Remote Key Loading methodology of a preferred embodiment of the present invention, a key can be enciphered under one of three possible schemes by the RKX service resulting in asymmetric encrypted output, symmetric encrypted output, or both. (1) Using the RKX service, a key may be enciphered under a public key located in an input parameter certificate. The certificate will contain a digital signature, which must be verified with a root public key located in the trusted block input parameter. The output will be placed into the asymmetric encrypted key output parameter. (2) Using the RKX service, a key may be enciphered under a DES key located in the transport key input parameter. The output will be placed into the symmetric encrypted key output parameter. (3) Using the RKX service, an external CCA token containing a variant and no control vector, may be decrypted under the importer key located in the importer key input parameter, then encrypted under the master key to produce an internal CCA token as output. The internal CCA token will contain a CV that is located within the trusted block's Common Import Key Parameters subsection of the rule section selected by the RKX service's rule ID input parameter.

The key that is output by the RKX service may be randomly generated within the adapter. When this is the case, the output will include a symmetric encrypted key and an optional asymmetric encrypted key. Symmetric encrypted output key format for this randomly generated key is always the RKX token format, encrypted under a variant of the MAC key. Asymmetric encrypted output key format may be either RSA OAEP or PKCS 1.2 format according to the rule section in the trusted block whose rule ID matches the rule ID input parameter. The public key contained in the input certificate parameter is used to encrypt the generated key.

The RKX service will generate a random number key whose length is defined by the rule section in the trusted block that was selected by the rule ID input parameter. The output produced will consist of a symmetric encrypted external RKX token and optionally, an asymmetric encrypted key enciphered under the public key contained in the certificate input parameter. In the preferred embodiment, the output of this generate routine will never be an external CCA token. In order to create an output external CCA token from random number key generation, the RKX service may be invoked twice; once to generate the RKX token, and subsequently to use the newly generated RKX token as an input parameter source key identifier in a call to the RKX service. In this subsequent call, a rule ID may be provided to the RKX service that selects a rule different from the first rule ID used to generate the RKX token, and which defines the “export” of the source key (e.g. an RKX token) to an external CCA token.

The key that is to be exported by the RKX service is not limited to being a source key in the form of an RKX token. Additionally, the key to be exported may be an encrypted form of a preexisting key that is supplied to the RKX service as a source key parameter in the form of an internal CCA DES token or an external CCA DES token. Four basic steps are involved in exporting a preexisting key by the RKX service.

In step one, the encrypted source key input parameter is converted into cleartext form. If the source key is an RKX key token—the key must be decrypted under a fixed variant of the MAC key that is located within the trusted block input parameter, provided that the rule ID in the RKX token matches the rule ID contained in the Rule Section of the trusted block. The MAC key in the trusted block must be decrypted under a fixed variant of the PKA master key before being used to decrypt the key in the RKX token. If the source key is an external CCA key token, the key must be decrypted under the importer key encrypting key input parameter, which first must be decrypted by the DES master key. If the source key is an internal CCA key token—the key must be decrypted under the DES master key.

In step two, the source key now in cleartext form is optionally checked and modified. If the source key input parameter was either an internal CCA key token or external CCA key token, the source key's control vector (CV) is checked for acceptability for key exportation. The trusted block's CV Mask determines which source key CV bits should be checked. The trusted block's CV Limit Template contains the required values for those source key CV bits that are to be checked. The CV mask and template are located in the trusted block's rule section that is selectable by the rule ID input parameter to the RKX service. If the source key input parameter is a key label for an internal CCA key token that is contained in key storage, verify that the label is valid by comparing it to the Source Key Label Template in the trusted block's rule section that is selectable by the rule ID input parameter to the RKX service. For the modification phase of step two, optionally apply the output key variant to the cleartext source key using an exclusive-or technique if specified to do so in the trusted block's rule section that is selected by the rule ID input parameter.

Step three is performed when the symmetric encrypted output key is determined to be in a CCA token format. In step three, the transport key is prepared for use on the modified source key from the previous step. The transport key may be either an RKX key token or an internal DES key token. Preparation of the transport key involves the optional application of a transport key variant and the optional application of a control vector. Both the transport key variant and control vector are found in the trusted block's rule section that is selected by the rule ID input parameter. If the transport key is contained in an RKX key token, the key must be decrypted under a fixed variant of the MAC key located within the trusted block input parameter, provided that the rule ID in the RKX token matches the rule ID contained in the rule section of the trusted block. The MAC key in the trusted block must be decrypted by the fixed variant of the PKA master key before being used to decrypt the transport key in the RKX token. If the transport key is an internal CCA token, the key must be decrypted under the DES master key.

A variant may be applied to cleartext transport key using an exclusive-or technique, if there is a transport key variant specified in the trusted block's rule section that is selected by the rule ID input parameter. Next, if there is a CV specified in the trusted block's rule section that is selected by the rule ID input parameter, the CV is applied to the transport key. If both the variant and the CV are applied to the cleartext transport key, then the variant is applied first, then the CV.

In step four, the rule section within the trusted block may indicate that the symmetric encrypted output should be either an RKX key token encrypted under a variant of the MAC key, or a CCA key token. If the former is true, the transport key is ignored. If the latter is true, optionally encipher the modified (or unmodified) source key from step two with the modified (or unmodified) transport key from step three according to the rule section in the trusted block whose rule ID matches the rule ID input parameter. If a CV was applied to the transport key in step three, then the output symmetric encrypted CCA token will also contain this same CV. Likewise if no CV was applied to the transport key, then the output encrypted CCA token will contain a zero CV.

The key that is to be imported by the RKX service is limited to being a source key in the form of an external CCA token, encrypted under a variant of a transport key, and containing no CV. Three basic steps are involved in importing a preexisting key by the RKX service.

In step one, the encrypted source key input parameter is converted into cleartext form. The key must be decrypted under the importer key encrypting key input parameter, which first must be decrypted.

If the importer key is contained in an RKX key token, the key must be decrypted under a fixed variant of the MAC key located within the trusted block's Protected Information subsection, provided that the rule ID in the RKX token matches the rule ID contained in the Import Key Rule Reference subsection of the selected rule in the trusted block. The MAC key in the trusted block must be decrypted by a fixed variant of the PKA master key before being used to decrypt the importer key in the RKX token. The importer key's length is checked against the minimum and maximum allowable sizes found in the trusted block's Common Import Key Parameters subsection.

If the importer key is an internal CCA token, the key must be decrypted under the DES master key. The importer key's length is checked against the minimum and maximum allowable sizes found in the trusted block's Common Import Key Parameters subsection. The importer key's control vector (CV) is checked for acceptability for use in the key importation phase. The trusted block's Import Key CCA Token Parameters “Import Key CV Mask” determines which importer key CV bits should be checked whereas the “Import Key CV Limit Template” contains the required values for those importer key CV bits that are to be checked. If the importer key input parameter is a key label for an internal CCA key token that is contained in key storage, verify that the label is valid by comparing it to the “Import Key Label Template” in the trusted block's Import Key CCA Token Parameters subsection.

In step two, once the source key is in cleartext form, it is optionally modified. For the modification phase of step two, apply the output key variant (if present) found in the Common Import Key Parameters subsection, to the cleartext source key using an exclusive-or technique if the output key variant length is nonzero.

In step three, the rule section within the trusted block may indicate that the symmetric encrypted output should be an internal CCA key token. This will be the only encrypted output form allowed for an import operation. The key from step two is encrypted under the DES master key using the transport key CV specified in the trusted block's Common Import Key Parameters subsection, and the output symmetric encrypted internal CCA token will also contain this same CV. If no CV was specified in the Common Import Key Parameters subsection, then the output encrypted CCA token will contain a zero CV.

For asymmetric encrypted output, encipher the key under the public key contained in the certificate input parameter to the RKX service. This encipherment will follow the format option according to the rule section in the trusted block whose rule ID matches the rule ID input parameter. The output option may be either RSA OAEP or PKCS1.2 format.

The trusted block is a data structure that contains several sections. In a preferred embodiment there are 5 types of sections (Please note that those skilled in the art of data structure design may find a multitude of ways to design a trusted block): the Trusted Public Key section, the Trusted Block Information section, the Trusted Block Label section, the Application Defined Data section, and the Rule section. Some of these sections have subsections that will be defined in the paragraphs that follow. Preceding these main sections is a Trusted Block Key Token Header that contains a token identifier, a header structure version number, and length of the entire trusted block structure.

The Trusted Public Key section is optional and if present, only one such section is allowed in the trusted block. This section includes the public key itself including a set of flags to indicate how the public key is to be used. The section includes a section identifier to indicate “Trusted RSA Public Key”, a structure version number, length of the section, RSA public key exponent length in bytes, RSA public key modulus length in bits, RSA public key modulus length is bytes, RSA public key exponent, RSA public key modulus, and the flags. The flags field will indicate whether the public key contained in this section can be used in digital signature operations only, key management operations only, or both digital signature and key management operations.

The Trusted Block Information section is required and only one such section is allowed in the trusted block. The section includes a section identifier to indicate “Trusted Block Information”, a structure version number, length of the section, a flags field, one required subsection, and one optional subsection. The flags indicate whether the trusted block is in an inactive state or active state. The trusted block is created in the inactive state and placed into the active state under dual control by the TBC service. A required subsection, named the Protection Information subsection, includes: the encrypted form of an 8 byte confounder and 24 byte MAC key, an 8 byte ISO-16609 CBC mode TDES MAC value, and a 16 byte PKA master key verification pattern computed using MDC4. The PKA master key verification pattern is set to zero if the trusted block is external, meaning that the confounder and MAC key are encrypted under a key encrypting key. The PKA master key verification pattern is nonzero when the trusted block is internal, meaning that the confounder and MAC key are encrypted under a fixed variant of the PKA (or asymmetric) master key. An optional subsection, named the Activation and Expiration Date subsection, includes: flags indicating whether or not the activation and expiration dates should be checked by the 4764 cryptographic adapter; activation date in year, month, day of month format; and expiration date in year, month, day of month format.

The Trusted Block Label section is optional and if present, only one such section is allowed in the trusted block. The section includes a section identifier to indicate “Trusted Block Label”, a structure version number, length of the section, and a label. In the preferred embodiment, the length of the label is 64 bytes. Host software can use this label to perform access control checking on the trusted block.

The Application Defined Data section is optional and if present, only one such section is allowed in the trusted block. The section includes a section identifier to indicate “Application Defined Data”, a structure version number, length of the section, length of the application data, and the application defined data. In a preferred embodiment, the length of the application data may be between 0 and 400 bytes inclusive. The application-defined data may be used to hold a public key certificate for the trusted public key contained in the Trusted Public Key section.

The Rule section is optional. Zero, one, or more than one, rule sections may be present in the trusted block. When a trusted block has zero rule sections, typically the Trusted Public Key section is present and the trusted block is used for digital signature verification purposes only. At least one rule section is required when generating a new random key, or exporting a preexisting key with the RKX service. Multiple rule sections are typically used whenever the RKX service is used to create a key hierarchy. The basic concept is that RKX tokens generated by the RKX service may be used as a source key and/or transport key in subsequent RKX service invocations using the same trusted block.

Each Rule section contains a section identifier, a structure version number, length of the section, rule ID, export/generate flag, generated key length, key check algorithm identifier, symmetric encrypted output key format flag, asymmetric encrypted output key format flag, and up to eight possible subsections. The subsections include: an optional Transport Key Variant subsection, an optional Transport Key Rule Reference subsection, a Common Export Key Parameters subsection that is required only if the RKX service is to export a preexisting key to an output format that is either an RKX token format or CCA token format, a Source Key Rule Reference subsection that is required only if the RKX service is exporting a source key that is in RKX token format, an Importer Key Rule Reference subsection that is required if the importer key is an RKX token, a Common Import Key Parameters subsection that is required when importing a key, an optional Import Key CCA Token Parameters subsection used when the import key parameter is in the form of a CCA token, and an optional Export Key CCA Token Parameters subsection. The latter subsection is used when the source key input parameter is a CCA token. The key type of the CCA token can be filtered by using the CV limit mask and template contained in the subsection.

The rule ID field of the Rule section is a value identifying the rule. The rule ID for one rule section must differ in value from rule IDs used in other rule sections within the trusted block. A particular Rule section is chosen for use by the RKX service according to the value of the Rule ID input parameter of the RKX service.

The export/import/generate flag in the Rule section indicates whether a new key should be generated or whether a preexisting key located in the source key input parameter, should be exported or imported. If a key is to be generated, the “generated key length” field will indicate the length in bytes of the generated key.

The key check algorithm identifier field may indicate either “no action” in which case no key check value is computed, encrypt an 8-byte block of binary zeroes with the key, or compute the MDC2 hash of the key and return the 16 byte value. For the case when the key check algorithm specifies an encryption of an 8-byte block of binary zeroes, and if the key to be generated or exported is single length, then the key encodes the 8 bytes of zeroes. If the key to be generated or exported is double length, the key triple encodes the 8-byte value as follows: the left half key encodes the 8-byte zero value, this result is decoded by the right key half, and that result is encoded by the left key half. If the key is single length, return the leftmost 3 or 4 bytes of the result of the encryption according to the value of the key check length input parameter as follows: (1) if the key is single length and if the key check length input parameter is set to 3, then 3 bytes will be returned. (2) If the key is single length and if the key check length input parameter is set to a value between 4 and 8 bytes inclusive, 4 bytes will be returned. (3) If the key is longer than single-length, return the entire 8 byte encryption result. Under no circumstances will there be 1, 2, 5, 6, or 7 byte encryption result returned.

The symmetric encrypted output key format flag indicates the output symmetric key formats allowed by the rule section. The output may be either an RKX token encrypted under a variant of the MAC key, or a CCA token encrypted under a transport key, or a CCA token encrypted under the DES master key. Note that the latter is only permitted for the import operation. The transport key input parameter to the RKX service may be an RKX token, a CCA token, or a label of a CCA token. A transport key variant contained in the Transport Key Variant subsection and/or a control vector contained in the Common Export Key Parameters subsection may be applied to the transport key. If both are applied, the variant is applied first, and then the control vector.

The asymmetric encrypted output key format flag indicates the output asymmetric key formats allowed by the rule section. Either no asymmetric key should be output, asymmetric output should be in PKCS 1.2 format, or asymmetric output should be in RSA-OAEP format. This latter format can make use of the Extra Data input parameter to the RKX service.

The Rule section's Transport Key Variant subsection is optional. If present, the subsection includes a tag identifier to indicate “Transport Key Variant”, length of the subsection, a structure version number, length of the variant, and the variant. The variant is to be exclusive-OR'ed (XOR) into the cleartext transport key. The length of the variant must be greater than or equal to the length of the transport key that is supplied to the RKX service when this rule is used. If the variant is longer than the transport key, it is truncated on the right to the length of the key before it is used. This variant is used if two conditions are satisfied: the length of the variant must be nonzero, and the output symmetric encrypted key format is set to indicate CCA token format. Transport keys are not used for output symmetric encrypted keys that are RKX tokens.

The Rule section's Transport Key Rule Reference subsection is optional but should be present if the transport key input parameter to the RKX service is an RKX token, otherwise the RKX token transport key will not be accepted for use. If present, the subsection includes a tag identifier to indicate “Transport Key Rule Reference”, length of the subsection, a structure version number, and the rule ID. The rule ID identifies the rule section that must have been used to create the RKX token transport key.

The Rule section's Import Key Rule Reference subsection is optional but should be present if the importer key input parameter to the RKX service is an RKX token, otherwise the RKX token import key will not be accepted for use. If present, the subsection includes a tag identifier to indicate “Importer Key Rule Reference”, length of the subsection, a structure version number, and the rule ID. The rule ID identifies the rule section that must have been used to create the RKX token importer key.

The Rule section's Common Export Key Parameters subsection is required for a key export request to the RKX service. The subsection includes a tag identifier to indicate “Common Export Key Parameters”, length of the subsection, a structure version number, the exported key's minimum length in bytes which also applies to the source key input parameter, the exported key's maximum length in bytes which also applies to the source key input parameter, the output key variant length in bytes, the output key variant, the length of the CV in bytes, and the CV. If the output key variant length is zero, then the output key variant is not used. Otherwise, the output key variant will be exclusive-OR'ed with the cleartext value of the key being exported (or generated). This variant must be at least as long as the longest key that will be exported using the rule, or as long as the key being generated using the rule. If the variant is longer than the key, the leftmost bytes of the variant are used, up to the key length. e.g. if the variant is 24 bytes and the key is 16 bytes, the first 16 bytes of the variant are exclusive-OR'ed with the key and the remaining 8 bytes of the variant are not used. The CV within this subsection, if used, will be exclusive-OR'ed with the transport key.

The Rule section's Common Import Key Parameters subsection is required for a key import request to the RKX service. The subsection includes a tag identifier to indicate “Common Import Key Parameters”, length of the subsection, a structure version number, the importer key's minimum length in bytes, the importer key's maximum length in bytes, the output key variant length in bytes, the output key variant which is applied to the cleartext value of the key being imported, the length of the CV in bytes, and the CV for the key being imported. If the output key variant length is zero, then the output key variant is not used. Otherwise, the output key variant will be exclusive-OR'ed with the cleartext value of the key being imported. This variant must be at least as long as the longest key that will be imported using the rule. If the variant is longer than the key, the leftmost bytes of the variant are used, up to the key length. e.g. if the variant is 24 bytes and the key is 16 bytes, the first 16 bytes of the variant are exclusive-OR'ed with the key and the remaining 8 bytes of the variant are not used. The CV within this subsection, if used, will be exclusive-OR'ed with the master key prior to encryption under the master key, per CCA practice.

The rules governing the usage of the control vector (CV) in the Common Export Key Parameters subsection that are defined whenever the symmetric encrypted output key is to be a CCA token format, are as follows:

(1) If the length of the CV in this subsection is zero, and if the source key input parameter is a CCA token, then the source key's CV will be used when encrypting the source key under the transport key. The source key's CV will be preserved in the symmetric encrypted output if the output is to be in the form of a CCA token. If the length of the CV in this subsection is zero, and if the source key input parameter is an RKX token, then no CV will be used.

(2) If the length of the CV in this subsection is nonzero, then it must be greater than or equal to the length of the source key input parameter. The CV length in this subsection may be either single or double length. If the source key is single length, and if the CV length in this subsection is double length, and if the left half of the double length CV in this subsection is nonzero with key form bits set to “single length key”, then the right half of this double length CV will be ignored. Note: CCA service CVG (Control Vector Generate) will generate a CV for a single length key by building a CV of double length with the right half of the CV set to binary zeroes. This CV may be placed into this subsection when building the trusted block.

(3) If the CV length in this subsection is double length and the CV is equal to 16 bytes of binary zeroes, then all CV bit definitions are ignored. Furthermore, if the symmetric encrypted output key is in CCA token format, the token will have a flag set to indicate that a CV is present, but the CV value in the output CCA token will contain 16 bytes of binary zeroes. Furthermore, if the source key input parameter is a single length key, the key will not be replicated to a double length key.

(4) If the access control point for “Replicate Key Allowed” is active, and if the source key input parameter contains a single length key in either RKX token or CCA token format, and if the CV in this subsection is double length with both halves nonzero, and if the CV's key form bits do not specify “single length key” and do not specify “guaranteed unique halves”, then the key in the source key input parameter is replicated, meaning that both halves of the double length key are identical in value.

(5) If the symmetric encrypted output key format flag is set to indicate that an RKX token will be output by the RKX service, then the CV in this subsection will be ignored since a transport key is not used for output symmetric RKX tokens.

The Rule section's Source Key Rule Reference subsection is optional but must be present if the source key input parameter to the RKX service is an RKX token, otherwise the RKX token source key will not be accepted for use. If present, the subsection includes a tag identifier to indicate “Source Key Rule Reference”, length of the subsection, a structure version number, and the rule ID. The rule ID identifies the rule section that must have been used to create the RKX token source key.

The Rule section's Export Key CCA Token Parameters subsection is optional for key export of CCA tokens. If using a CCA token as a source key input parameter, its key type can be “filtered” by using the CV limit mask and template in this subsection. If present, the subsection includes a tag identifier to indicate “Export Key CCA Token Parameters”, length of the subsection in bytes, a structure version number, the export key CV limit mask length in bytes, the export key CV limit mask, the export key CV limit template, the source key label template length in bytes, and the source key label template.

If the export key CV limit mask length is zero, then the export key CV limit mask and the export key CV limit template are both nonexistent. The export key CV limit mask and the export key CV limit template work together to restrict the acceptable control vectors for CCA keys to be exported. The CV limit mask indicates which CV bits should be checked. The CV limit template contains the required values for those CV bits that are to be checked. The CV for the key to be exported is first AND'ed with the CV Limit Mask, and then the result is compared with the CV Limit Template. If the two do not match, the request is rejected with an error. The export key CV limit mask length must not be less than the Export Key Minimum Length set in the Common Export Key Parameters subsection. The export key CV limit mask length must be equal in length to the actual length of the source key input parameter to the RKX service, otherwise the RKX service request will be rejected with an error.

The source key label template length in bytes must be set to either 0 or 64. No other values are allowed. If this length is zero and a source key label is present, then the label will not be checked. If this length is 64 and a source key label is not present, an error will be returned by the RKX service. A single asterisk (wildcard) in the source key label template field will not be interpreted to accept the absence of a source key label. In the preferred embodiment, if the source key label template length is nonzero, the label template is left justified in the source key label template field. The label template must conform to the following rules in the preferred embodiment (note that other methodologies may be employed): The first character cannot be between 0x00-0x1F, nor can it be 0xFF; the first character cannot be numeric, 0x30-0x39; a label is terminated by a space on the right; the only special characters permitted are 0x23 (#), 0x24 ($), 0x40 (@), 0x2E (.), and wildcard 0x2A (*); the wildcard 0x2A (*) is permitted as the first character, the last character, or only character; once a space is encountered, every character to the right up to the 64 byte length must be spaces; only alphanumeric characters are allowed a-z, A-Z, 0-9, the aforementioned four special characters, the wildcard (*), and the space (0x20).

The Rule section's Import Key CCA Token Parameters subsection is optional for key import of CCA tokens. If using a CCA token as a importer key input parameter, its key type can be “filtered” by using the CV limit mask and template in this subsection. If present, the subsection includes a tag identifier to indicate “Import Key CCA Token Parameters”, length of the subsection in bytes, a structure version number, the import key CV limit mask length in bytes, the import key CV limit mask, the import key CV limit template, the import key label template length in bytes, and the import key label template.

If the import key CV limit mask length is zero, then the import key CV limit mask and the import key CV limit template are both nonexistent. The import key CV limit mask and the import key CV limit template work together to restrict the acceptable control vectors for CCA importer key to be used in the importation operation. The CV limit mask indicates which CV bits should be checked. The CV limit template contains the required values for those CV bits that are to be checked. The CV for the importer is first AND'ed with the CV Limit Mask, and then the result is compared with the CV Limit Template. If the two do not match, the request is rejected with an error. The import key CV limit mask length must not be less than the Import Key Minimum Length set in the Common Import Key Parameters subsection. The import key CV limit mask length must be equal in length to the actual length of the importer key input parameter to the RKX service, otherwise the RKX service request will be rejected with an error.

The import key label template length in bytes must be set to either 0 or 64. No other values are allowed. If this length is zero and an import key label is present, then the label will not be checked. If this length is 64 and an import key label is not present, an error will be returned by the RKX service. A single asterisk (wildcard) in the import key label template field will not be interpreted to accept the absence of an import key label. In the preferred embodiment, if the import key label template length is nonzero, the label template is left justified in the import key label template field. The label template must conform to the following rules in the preferred embodiment (note that other methodologies may be employed): The first character cannot be between 0x00-0x1F, nor can it be 0xFF; the first character cannot be numeric, 0x30-0x39; a label is terminated by a space on the right; the only special characters permitted are 0x23 (#), 0x24 ($), 0x40 (@), 0x2E (.), and wildcard 0x2A (*); the wildcard 0x2A (*) is permitted as the first character, the last character, or only character; once a space is encountered, every character to the right up to the 64 byte length must be spaces; only alphanumeric characters are allowed a-z, A-Z, 0-9, the aforementioned four special characters, the wildcard (*), and the space (0x20).

The sequence of services leading up to the RKX service is as follows:

First a trusted block is created under dual control in two parts. An external trusted block is created with all its sections and subsections by one individual having a role and/or profile differing from a second individual's role and/or profile, by using the TBC service with keyword set to INACTIVE. The confounder and MAC key contained in the trusted block's Protection Information subsection under the Information section is encrypted under a variant of the IMP-PKA key encrypting key located in the transport_key_identifier input parameter. The trusted block is termed inactive because its flag in the trusted block Information section is set to “inactive”. The second individual having a role and/or profile differing from the first individual uses the TBC service with keyword set to ACTIVATE. The flag in the trusted block information section is set to “activated”, making the resulting trusted block “active”.

Second, the active trusted block is provided as an input parameter to the PKI service, which in turn converts the trusted block to internal format, by virtue of the fact that the MAC key contained within the trusted block will be encrypted under a fixed variant of the PKA (or asymmetric) master key.

Finally, the internal format of the trusted block is now ready to be used as an input parameter to the RKX service.

The RKX uses a special structure to hold encrypted symmetric keys in a way that binds them to the trusted block, and allows sequences of RKX calls to be bound together as if they were an atomic operation. Table 18 shows a conceptual view of the RKX key structure, which is also known as an RKX key Token.

TABLE 18 Offset Length (bytes) (bytes) Description of RKX token field 0 1 Token Type 0x02 (external key token) 1 3 Reserved, must be 0x00.00.00 4 1 Version Number 0x10 5 1 Reserved, must be 0x00 6 1 Flag (reserved, must be 0x00) 7 1 Key length in bytes, including confounder 8 32 Encrypted confounder and key. 40 8 Rule ID for the trusted block rule section that was used to create this RKX token. 48 8 Reserved, must be filled with 0x00 bytes. 56 8 MAC Value - ISO-16609 TDES CBC-mode MAC. The MAC is computed over the 56 bytes starting at offset 0 in this token, and including the encrypted key value and the rule ID using the same MAC key that is used to protect the trusted block itself.

The confounder begins at offset 8 and the key begins at offset 16. The key field uses 8, 16, or 24 bytes to hold its value. Unused bytes in this field must be set to 0x00. The key is left justified starting at offset 16 in the event that the key is less than 24 bytes in length. The layout of the confounder and key is as follows: confounder (8 bytes), key left (8 bytes), key middle (8 bytes), and key right (8 bytes).

A fixed, randomly derived variant is exclusive-OR'ed with the MAC key located within the trusted block in the Trusted Block Information section before it is used to encipher or decipher the generated or exported confounder and key at offset 8 of the RKX key token above. The random variant has the following hex value:

EB 4B 1D F5 D8 1B 63 8D-5F DE 17 B1 00 27 35 AC-55 BB 05 78 AF DI B8 18

The MAC key within the trusted block, when in internal format, can be recovered by decipherment under the PKA master key. The trusted block is originally created in external form by the TBC service and then converted to internal form by the PKI service (Note that this PKI service implements the Trusted Block Import Function), prior to the RKX call. A fixed, randomly derived variant is exclusive-OR'ed with the PKA master key before it is used to encipher or decipher the MAC key within the trusted block when the trusted block is in internal format. The random variant has the following hex value: C9 2E BB 35 D2 AA56 D8-9C 66 E4 12 2B E7 A0 A3-B4 55 FF E4 D7 E7 F6 41

A call to the RKX service can use an RKX token and a trusted block whose rule section references the rule ID that must have been used to create the RKX token. The trusted block rule section's Rule ID can be compared with the RKX token's Rule ID for verification purposes.

In the preferred embodiment, the Rule ID is an 8-byte ASCII character string, with no null terminator. The acceptable characters for the Rule ID are A-Z, a-z, 0-9, - (hyphen), and _ (underscore). If the Rule ID is less than eight characters long, it must be left justified and padded on the right with space characters. Other implementations besides the preferred embodiment may use other characters.

The MAC value at offset 56 guarantees that the key and the rule ID cannot be modified without detection, providing integrity, and binding the rule ID to the key itself. In addition, the MAC will only verify with the same trusted block that created the key, thus binding the key structure to that specific trusted block.

FIG. 6 together with table 19 highlight the major steps involved in the Remote Key Export methodology (RKX Service—main( )).

TABLE 19 Step number and brief summary Detailed description 600, 602 - Validate See FIG. 7 - validate_block( ) for details. Verify that all the trusted block these conditions are met: A. No unknown sections have been built into the trusted block, B. The trusted block token identifier is internal, C. The Active flag is enabled, D. Fields within the trusted block have valid lengths and valid values. If these conditions are not met, abort operation with an error. 604 - Recover See FIG. 8 - decrypt_tb_mac_key( ) for details. trusted block MAC A. Decrypt the confounder and MAC key located in the key Protection Information section of the trusted block under a variant of the PKA Master Key and using an IV of binary zeroes. B. The variant is the following hexadecimal string where each byte has even parity so that the parity of the XOR result of the PKA master key with the variant is not altered: C9 2E BB 35 D2 AA 56 D8 - 9C 66 E4 12 2B E7 A0 A3 - B4 55 FF E4 D7 E7 F6 41. C. Decryption is performed using triple DES CBC mode. 606 - Compute See FIG. 9 - compute_tb_mac( ) for details. MAC value over A. Copy the trusted block to some temporary_block. the trusted block B. Fill in the following Protection Information section fields of the temporary block with binary zeroes: encrypted MAC key, ISO-16609 TDES CBC MAC value, MKVP (master key verification pattern). C. Compute an ISO-16609 CBC mode TDES MAC over the entire temporary block contents using the recovered TDES MAC key and an IV of binary zeroes. 608 - Computed The computed MAC from step 3 is compared to the MAC value MAC = stored contained in the trusted block Protection Information section. trusted block A. If equal, proceed to step 610, MAC? B. Else, abort operation with an error. 610 - Verify the This routine obtains the MDC4 hash of the current PKA master MKVP in the key and compares the result to the MKVP contained in the trusted block Protection Information section of the trusted block. If a mismatch occurs, the MDC4 hash of the old PKA master key is obtained and compared to the MKVP contained in the Protection Information section of the trusted block. If a mismatch still occurs, abort the operation with an error. 612 - Locate rule Locate a Rule section in the trusted block with an ID equal to section in trusted the value in the input parameter, rule_id. This will be the rule block section that is used during the RKX service being requested. If not found, abort operation with an error. 614 - Is the If all the following conditions are true, proceed to step 616. transport KEK Else, proceed to step 618. needed? A. A transporter KEK was provided in the transport key identifier input parameter, or a transporter KEK key label was provided in the transport key identifier input parameter. In the latter case, retrieval of the transporter KEK from the key storage repository was successful. B. The rule section in the trusted block selected in step 612 indicates that an export key operation is to take place. C. The rule section in the trusted block selected in step 612 indicates that the symmetric encrypted key output is to be in CCA token format. 616 - Process See FIG. 10 - process_transport_key( ) for details. transport KEK A. If the transporter KEK is a CCA token, triple decrypt the transporter KEK under the DES master key using the transport KEK's CV. B. If the transporter key is an RKX token, decrypt the confounder and key contained in the token, under a variant of the MAC key located in the trusted block's Protection Information section. C. If a transport key variant exists in the trusted block rule section selected in step 612, then XOR the transport key variant with the cleartext transport key. 618 - Is the If the following conditions are true, proceed to step 620. Else, importer KEK proceed to step 622: needed? A. An importer KEK was provided in the importer key identifier input parameter, or an importer KEK key label was provided in the importer key identifier input parameter. In the latter case, retrieval of the importer KEK from the key storage repository was successful. B. The rule section in the trusted block selected in step 612 indicates that an export key operation is to take place. 620 - Process See FIG. 11 - process_importer_key( ) for details. importer KEK A. If the operation is export, verify that the importer key's CV is an IMPORTER type. B. If the operation in import and the importer key is a CCA token, verify that the importer key's CV matches the Import Key CV mask and template in the Import Key CCA Token Parameters. C. If the importer key is a CCA token, triple decrypt the importer key under the master key with importer key's CV. D. If the importer key is an RKX token and the operation is import, verify that the importer key's rule ID matches the Import Key Rule Reference, and decrypt the confounder and key contained in the token, under a variant of the MAC key located in the trusted block's Protection Information section. 622 - Exporting or If the following conditions are true, proceed to step 624. Else, importing a key? proceed to step 630: A. A source key was provided in the source key identifier input parameter, or a source key label was provided in the source key identifier input parameter. In the latter case, retrieval of the source key from the key storage repository was successful. B. The rule section in the trusted block selected in step 612 indicates that an export key operation is to take place. 624 - Process See FIG. 12 - process_source_key( ) for details. Process the source key source key differently according to whether the source key is an RKX token, an internal CCA token, or external CCA token. A. If the source key is an RKX token, decrypt the confounder and key contained in the token, under a variant of the MAC key located in the trusted block's Protection Information section. B. If the source key is either an external or internal CCA token, verify the source key's CV against the trusted block's selected rule section's CV mask and template. Verify that the key may be exported (if an export operation is to take place). Verify that if the source key was a key label, the trusted block's rule section's key label template allows the source key's label. C. If the source key is an external CCA token, then decrypt the key contained in the token, under the importer KEK from step 620. D. If the source key is an internal CCA token, triple decrypt the key under the master key with source key's CV. If the source key is single length, and if key replication is allowed, replicate the single length key to a double length key. E. If the operation is import and if an output key variant exists in the Common Import Key Parameters subsection of the trusted block rule, apply the variant to the cleartext source key. 626 - Exporting a If the following conditions are true, proceed to step 628. Else, key to CCA token proceed to step 630: format? A. The rule section in the trusted block selected in step 612 indicates that an export key operation is to take place. B. The rule section in the trusted block selected in step 612 indicates that the symmetric encrypted output format is to be a CCA token format. 628 - Verify If the transporter key is an RKX token, double length, with transport KEK has equal halves; or if the transporter key is a CCA token, type unique halves EXPORTER, with equal halves, then abort operation with an error. 630 - Asymmetric If the rule section in the trusted block selected in step 612 encrypted output indicates that an asymmetric encrypted key will be output, then needed? proceed to step 632, otherwise proceed to step 640. 632 - Trusted block When producing asymmetric encrypted key output and if the public key exists? trusted block does not have a Trusted Public Key section, abort the operation with an error. 634 - Trusted block When producing asymmetric encrypted key output, verify that public key usage the trusted block's Trusted Public Key section has a public key correct? usage flag consistent with the RKX service. This implies that the key usage flag be set to allow either key management operations only, or both digital signature and key management operations. If the key usage flag is set to allow digital signature operations only, then abort the operation with an error. 636 - Verify input See FIG. 13 - verifyCertParms( ) for details. This routine certificate verifies the validity of the certificate_parms_length input parameters parameter as well as the lengths contained in the certificate parms table. The lengths in the certificate parms table include modulus length, exponent length, digital signature length, and length of the certificate data hashed to compute the digital signature. The lengths of these parameters contained in the certificate along with their offsets, are used to determine if the parameters overlap, which would indicate an error. 638 - Hash the Compute the SHA-1 hash on the certificate input parameter certificate and located by adding the offset of the first byte of certificate data verify its signature. to be hashed (the offset being located in the certificate parms input parameter) to the beginning of the certificate input parameter for a length found in the certificate parms input parameter that represents the amount of data to be hashed. Once the hash is obtained, prepend the BER encoded string to hash. Verify certificate signature using the PKCS 1.0/1.1 encryption method . . . 640, 642, 644 - Referring to the rule section in the trusted block selected in Generate, import, step 612, determine whether to generate a key or export a key. or export a key? A. If generating a new key, proceed to FIG. 14 - rkx_generate( ). B. If exporting a preexisting key found in the source key identifier input parameter, proceed to FIG. 15 - rkx_export( ). C. If importing a preexisting key found in the source key identifier input parameter, encrypt the source key from step 624 under the master key using the supplied transport CV in the Common Import Key Parameters subsection in the trusted block rule. Once a key is either generated, imported, or exported, or if an error occurred in the process that would prematurely abort the process, a response message is built to send to the host from the cryptographic adapter as described in the next step, step 646. 646 - Send a data A. A symmetric encrypted output key will always be returned packet to the host to the host from the cryptographic adapter from this containing the service. symmetric B. An asymmetric encrypted key may or may not be returned encrypted output based upon the contents of the rule section selected in step key, optional 612. For example, if the rule section's Asymmetric asymmetric Encrypted Output Key Format flag is set to “no encrypted output asymmetric key”, then only a symmetric encrypted key key, and optional will be returned to the host. key check value. C. The key check value may or may not be returned based upon the contents of the rule section selected in step 612. If the rule section's Key Check Algorithm identifier field specifies “Do not compute a key check value”, then no key check value will be returned and the key check value length will be set to zero. Otherwise return the key check value from FIG. 17, step 614 (if the RKX service generated a key) or from FIG. 18, step 606 (if the RKX service exported a key). 648 - RKX The service is complete. complete

FIG. 7 together with table 20 provide the major steps involved in the routine that verifies the validity of the trusted block for use by the call service (validate_block( )).

TABLE 20 Step number and brief summary Detailed description The Validate_block routine (700) verifies that the trusted block is valid for use by the calling service. 702 - Parse the This routine will parse the trusted block; filling in a buffer that trusted block. holds a table of pointers to structures that hold the counts of each section, the pointers to these sections, and the pointers to each section's required and/or optional subsections. This routine will: A. Verify that the total size of the trusted block is equal to the sum of the lengths of all sections, then B. Locate and save the Active flag contained in the Information section. The table of pointers to these structures will be organized in such as way as to easily locate a particular section and subsection within the trusted block, whose sections and subsections may be organized in any order upon creation of the trusted block. 704 - Verify This routine will: validity of the A. Verify the existence of the Information section, Information B. Verifies that the length of the section is not less than the section sum of the lengths of the subsections; namely, the Protection Information section (required to be present) and the Activation and Expiration Date subsection (optionally present), C. Verifies that there is only one Protection Information subsection, D. Verifies that the trusted block activation date is valid: month is in the range of 1-12; days are not zero; days not greater than the maximum number of days in the specified month, E. Verifies that the trusted block expiration date is valid; month is in the range of 1-12; days are not zero; days not greater than the maximum number of days in the specified month, F. Verifies that the activation date is less than or equal to the expiration date. G. Verifies that the expiration date is not less than or equal to the cryptographic adapter's real time clock data and time. 706 - Obtain the This routine verifies that the trusted block token is either internal state of the trusted or external, and active or inactive, based upon both the value of block the trusted block's token identifier located in the Trusted Block Key Token Header, and the service that called the validate_block routine. This routine verifies that only the TBC, PM, DSV, KTC, and RKX services call this routine. Any other service that calls this routine results in an error. A. If the TBC service calls validate_block with the INACTIVE keyword parameter, the token identifier in the Trusted Block Key Token Header is ignored and the active flag in the Trusted Block Information section is ignored. B. If the TBC service calls validate_block with the ACTIVATE keyword parameter, the token identifier in the Trusted Block Key Token Header must be an external token and the active flag in the Trusted Block Information section must be in the inactive state. C. If the RKX service calls validate_block, the token identifier in the Trusted Block Key Token Header must be an internal token and the active flag in the Trusted Block Information section must be in the active state. D. If the PKI service calls validate_block, the token identifier in the Trusted Block Key Token Header must be an external token and the active flag in the Trusted Block Information section must be in the active state. E. If the DSV service calls validate_block, the token identifier in the Trusted Block Key Token Header must be an internal token and the active flag in the Trusted Block Information section must be in the active state. F. If the KTC service calls validate_block, the token identifier in the Trusted Block Key Token Header must be an internal token and the active flag in the Trusted Block Information section must be in the active state. 708 - Verify This routine checks for the presence of Public Key section validity of the within the Trusted Block. If the Public Key section is present, Public Key the routine: section if present A. Verifies that the length of this section is greater than or equal to the sum of its constituent parts: section identifier, structure version number, length field, public key exponent byte length field, public key modulus bit length, public key modulus byte length, public key exponent, public key modulus, and usage flags; B. Verifies that the modulus bytes length is not trivial (i.e. zero length); C. Verifies that the exponent byte length is not trivial (i.e. zero length); D. Verifies that the modulus length in bits is not greater than the modulus length in bytes; E. Verifies that the modulus length in bits does not exceed the maximum value used for encrypting with symmetric RSA keys as set forth by the function control vector resident within the cryptographic adapter; F. Verifies that the modulus length in bits is not less than 512 bits; G. Verifies that the public key usage flags are set to a valid value; H. Verifies that the public key exponent has odd parity. 710 - Verify This routine verifies that the length of this section is valid and validity of the that the label contains valid characters. Wildcard characters are Label section if allowed. present 712 - Verify This routine verifies that the length of this section is valid. validity of the Application Defined Data section if present 714 - Verify This routine checks the validity of all rule sections present in the validity of all trusted block. At least one rule section must be present if the Rule sections that RKX service called the validate_block routine. are present A. Verify that the length of the rule section is greater than or equal to the sum of its constituent parts; defined as the sum of the section identifier, structure version number, length field, rule ID field, flags field, generated key length field, key check algorithm identifier, symmetric encrypted output key format flag, and asymmetric encrypted output key format flag. B. Verify that each rule ID field of each rule section is unique in value, i.e. not equal to another rule ID of another rule section contained in the trusted block. C. Verify that the rule ID is an ASCII string with no NULL terminator, and follows the acceptable character set of A-Z, a-z, hyphen (-), and underscore (_). If the rule ID is less than 8 characters, then the rule ID must be left justified and padded on the right with spaces. D. Verify that the Generated Key Length field is zero if the Flags field indicates that an export operation is to occur; and either 8 (for single length key), 16 (for double length key), or 24 (for a triple length key) if the Flags field indicates that a generate operation is to occur. E. Verify that the Key Check Algorithm field indicates that either: no key check should be done; the key check algorithm will involve encryption of 8 bytes of zeroes with the key being generated or exported; or an MDC2 hash of the generated or exported key will be performed. F. Verify that the Symmetric Encrypted Output Format flag is set to either RKX token format or CCA token format. G. Verify that the Asymmetric Encrypted Output Format is set to either no asymmetric output, PKCS1.2 formatted output, or RSA-OAEP formatted output. H. Verify that the lengths of the subsections in each rule section are valid, and that none of the subsections per given rule section are duplicated. I. Validity checks are tailored to each subsection as follows: J. For a Transport Key Variant subsection, verify that the transport key variant length, if not zero, should be at least as long as a single length key, and verify the transport key variant has even parity. K. For a Transport Key Rule Reference subsection, verify that the transport key rule ID is an ASCII string with no NULL terminator, and follows the acceptable character set of A-Z, a-z, hyphen (-), and underscore (_). If the rule ID is less than 8 characters, then the rule ID must be left justified and padded on the right with spaces. L. For an Import Key Rule Reference subsection, verify that the import key rule ID is an ASCII string with no NULL terminator, and follows the acceptable character set of A-Z, a-z, hyphen (-), and underscore (_). If the rule ID is less than 8 characters, then the rule ID must be left justified and padded on the right with spaces. M. For a Common Export Key Parameters subsection,  Verify that the Export Key Maximum Length is less  than or equal to the value of the CV Length field if the  CV length is not zero with the exception of the  following case: If the Export Key Maximum length is  24 bytes, then the CV Length may be equal to 16 bytes  if the CV value in this subsection is set to either all  binary zeroes, or all binary zeroes with the key-part bit  and parity bit turned on.  If the Output Key Variant Length is not zero, verify  that the Output Key Variant has even parity, verify that  its length is greater than or equal to the Generated Key  Length value in the Rule section if a generate operation  is to take place, and verify that its length is greater than  or equal to the Export Key Maximum Length in this  subsection if an export operation is to be performed.  If an export operation is to be performed, verify that the  Export Key Minimum Length is not zero, is a multiple  of 8 bytes, is not greater than 24 bytes, and is not  greater than the Export Key Maximum Length.  Furthermore, verify that the Export Key Maximum  Length is not zero, is a multiple of 8 bytes, and is not  greater than 24 bytes.  If the CV Length is not zero, perform the validity  checks on the CV in this subsection such that the CV  bits conform to control vector standards as documented  in the CCA Basic Services Reference and Guide  Appendix C: CCA control-vector definitions and key  encryption. N. For a Common Import Key Parameters subsection,  If the Output Key Variant Length is not zero, verify  that the Output Key Variant has even parity, verify that  its length is greater than or equal to the length of the  key to be imported, and verify that its length is greater  than or equal to the Import Key Maximum Length in  this subsection if an import operation is to be  performed.  If an import operation is to be performed, verify that  the Import Key Minimum Length is not zero, is a  multiple of 8 bytes, is not greater than 24 bytes, and is  not greater than the Import Key Maximum Length.  Furthermore, verify that the Import Key Maximum  Length is not zero, is a multiple of 8 bytes, and is not  greater than 24 bytes.  If the transport CV Length is not zero in this  subsection, perform the validity checks on the CV in  this subsection such that the CV bits conform to control  vector standards as documented in the CCA Basic  Services Reference and Guide Appendix C: CCA  control-vector definitions and key encryption. O. For a Source Key Rule Reference subsection, verify that the source key rule ID is an ASCII string with no NULL terminator, and follows the acceptable character set of A-Z, a-z, hyphen (-), and underscore (_). If the rule ID is less than 8 characters, then the rule ID must be left justified and padded on the right with spaces. P. For an Export Key CCA Token Parameters subsection,  Verify that if the Export Key CV Limit Mask Length is  nonzero, then its value is either 8 bytes or 16 bytes.  Furthermore, the Export Key CV Limit Mask's length  must equal the length of the Export Key CV Limit  Template.  Verify that the Source Key Label Template Length is  equal to either zero or 64 bytes. If the latter is true,  verify that there are no binary zeroes in the Source Key  Label Template field.  Verify that the CV Limit Mask Length is equal to the  Export Key Maximum Length field in the Common  Export key Parameters subsection.  If there are any invalid subsections encountered, abort  the operation with an error. Q. For an Import Key CCA Token Parameters subsection,  Verify that if the Import Key CV Limit Mask Length is  nonzero, then its value is either 8 bytes or 16 bytes.  Furthermore, the Import Key CV Limit Mask's length  must equal the length of the Import Key CV Limit  Template.  Verify that the Import Key Label Template Length is  equal to either zero or 64 bytes. If the latter is true,  verify that there are no binary zeroes in the Import Key  Label Template field.  Verify that the CV Limit Mask Length is equal to the  Import Key Maximum Length field in the Common  Import Key Parameters subsection.  If there are any invalid subsections encountered, abort  the operation with an error. 716 - Return to caller

FIG. 8 together with table 21 highlight the major steps involved in the routine that decryptes the MAC key of the trusted block for use by the call service (decrypt_tb_mac_key( )).

TABLE 21 Step number and brief summary Detailed description Decrypt trusted block MAC key 800 with either the old or current PKA master key according to whether the trusted block's MKVP matched the old or current PKA MKVP. A variant will be exclusive-OR'ed with the cleartext PKA master key before the decryption is performed. The decrypted 24-byte MAC key will be exclusive-OR'ed with a variant. 802 - This routine obtains the MDC4 hash of the current PKA Obtain master key and compares the result to the MKVP contained in PKA the Protection Information section of the trusted block. If a master mismatch occurs, the MDC4 hash of the old PKA master key key. is obtained and compared to the MKVP contained in the Protection Information section of the trusted block. If a mismatch still occurs, abort the operation with an error. 804 - The current or old master key, chosen based upon the match Triple found in step 802, is exclusive-OR'ed with the PKA master decrypt key variant, defined as 0xC9 2E BB 35 D2 AA 56 D8, 9C 66 MAC key E4 12 2B E7 A0 A3 B4 55 FF E4 D7 E7 F6 41. The confounder and MAC key located in the Protection Information of the trusted block is then triple decrypted using the cipher-block chaining mode. 806 - The MAC key variant, defined as 0xEB 4B 1D F5 D8 1B 63 XOR 8D 5F DE 17 B1 00 27 35 AC 55 BB 05 78 AF DI B8 18, is MAC exclusive-OR'ed with the cleartext MAC key. The key with confounder, having served its purpose in step 804, is ignored variant in this step. 808 - Return to caller.

FIG. 9 together with table 22 provide the major steps involved in the routine that computes a MAC value over a trusted block (compute_tb_mac( )).

TABLE 22 Step number and brief summary Detailed description The compute_tb_mac routine (900) computes the MAC over a trusted block. 902 - Copy trusted Copy trusted block to a temporary block. block to a temporary block 904 - Zeroize fields Fill the following temporary block fields with binary zeroes in the used to make the Protection Information section of the trusted block: MAC value and MAC key field that includes the confounder, MAC value which are parts of field, and MKVP field. the MAC value. 906 - Compute Compute ISO-16609 cipher-block chaining mode, triple DES MAC MAC value over temporary block using the cleartext MAC key obtained in FIG. 8, step 804. The cleartext MAC key does not have the MAC key variant exclusive-OR'ed to it during this step. 908 - Return to caller.

FIG. 10 together with table 23 highlight the major steps involved in the process transport key routine (1000) that verifies that the transporter key is either a valid RKX token or a valid CCA token (process_transport_key( )).

TABLE 23 Step number and brief summary Detailed description The process transport key routine 1000 verifies that the transporter key is either a valid RKX token or a valid CCA token. If valid, the key is decrypted. If a transport key variant exists, it is exclusive-OR'ed with the cleartext transport key. 1002 - Does This routine is called whenever the RKX service is to transporter key perform a key export operation. If the RKX API input exist? parameter, transport_key_identifier, contains a NULL token, defined as a token whose first byte is set to 0x00; or if the transport_key_identifier was NULL, then abort the operation with an error. 1004 - Is If the transporter key token type is external and the version transporter key an number is 0x10 indicating an RKX token, proceed to step RKX token? 1008. Else proceed to step 1006. 1008 - Decrypt the A. Verify that the RKX token's key length field is set transport key in the equal to the sum of either the confounder length and a RKX token. single length key, the confounder and a double length key, or the confounder and a triple length key. B. If the RKIX token's key length field is set equal to the sum of the confounder length and a single length key, abort the operation with an error because a transporter key must not be single length in the preferred embodiment. C. Using the trusted block's Protection Information section's cleartext MAC key exclusive-OR'ed with the MAC key variant from FIG. 8, step 806, compute the ISO-16609 cipher-block chaining mode triple DES MAC over the RKX token starting at offset 0 up to but not including offset 56 in Table 18. D. Compare computed MAC against RKX token MAC value at offset 56. If unequal, abort the operation with an error (1012). Else, decrypt the RKX token's confounder and key using the trusted block's Protection Information section's cleartext Mac key exclusive- OR'ed with the MAC key variant from FIG. 8, step 806. E. Verify that the trusted block's Transport Key Rule Reference subsection's rule ID matches the transporter key RKX token's rule ID at offset 40 of Table 18. If unequal, abort the operation with an error. F. Using the trusted block's Common Export Key Parameter's subsection, determine if the CV length for the key to be exported is nonzero. If nonzero, then verify that the RKX token's key length field is not set equal to the sum of the confounder length and a triple length key. If so, abort the operation with an error because a triple length transporter key is not compatible with control vectors. G. If a Transport Key Variant subsection within the Rule section exists, exclusive-or the variant contained in the Transport Key Variant subsection with the cleartext transporter key, saving the result for later use. H. If the transporter key does not have odd parity, create a warning message for the host response, but continue to use the transporter key I. Proceed to step 1014. 1006 - Is If the transporter key token type is internal, proceed to step transporter key an 1010. Else, abort operation with an error. internal CCA token? 1010 - Decrypt the A. Verify that the CCA token has a nonzero CV. Perform transporter key in the validity checks on the CV in this token such that the the CCA token. CV bits conform to control vector standards as documented in the CCA Basic Services Reference and Guide Appendix C: CCA control-vector definitions and key encryption. B. Verify the validity of the token validation value contained within the CCA token. C. Verify that the transporter key is a double length key. D. Using the transporter key token's MKVP, determine whether to use the current or old DES master key to decrypt the transporter key. Decrypt the transporter DES key under the corresponding DES master key using the transporter key token's CV according to the CCA Basic Services Guide and Reference Appendix C. E. If a Transport Key Variant subsection within the Rule section exists, verify that the transport key variant has even parity. If not, abort the operation with an error. F. If a Transport Key Variant subsection within the Rule section exists, exclusive-or the transport key variant with the cleartext transporter key. 1014 - Return to caller

FIG. 11 (process_importer_key( )) together with table 24 provide the major steps involved in the process of verifying the importer key, if present, is a valid internal CCA token.

TABLE 24 Step number and brief summary Detailed description The process importer key routine (1100) will verify that the importer key, if present, is a valid internal CCA token. If valid, the importer key is decrypted for later use. 1102 - Is the If the source_key_identifier is an RKX token which importer key requires the MAC key within the trusted block for needed? decryption, or if the source_key_identifier is an internal CCA token which requires a DES master key for decryption, then ignore the importer key and proceed to step 1114. Else, proceed to step 1104. 1104 - Does the If the importer_key_identifier contains a NULL token, importer key exist? defined as a token whose first byte is set to 0x00; or if the importer_key_identifier is NULL, and the source key is an external CCA token, abort the operation with an error. Else, proceed to step 1106. 1106 - Is the If the importer_key_identifier is an internal CCA token, importer key an proceed to step 1108. Else, proceed to step 1107. internal CCA token? 1107 - Is the If the importer key identifier is an RKX token, proceed to importer key an step 1109, else abort the operation with an error. RKX token? 1108 - Decrypt the A. Verify that the CCA token has a nonzero CV. importer key in the Perform the validity checks on the CV in this token CCA token such that the CV bits conform to control vector standards as documented in the CCA Basic Services Reference and Guide Appendix C: CCA control- vector definitions and key encryption. B. Verify the validity of the token validation value contained within the CCA token. C. Verify that the importer key is a double length key. D. Using the importer key token's MKVP, determine whether to use the current or old DES master key to decrypt the importer key. Decrypt the importer DES key under the corresponding DES master key using the importer key token's CV. E. If the importer key does not have odd parity, create a warning message for the host response, but continue to use the importer key. F. Proceed to step 1114. 1109 - Decrypt Decrypt the importer RKX token under a variant of the RKX token PKA master key and proceed to step 1114 1114 - Return to caller.

FIG. 12 (process_source_key( )) together with table 25 provide the major steps involved in the process of verifying if the source key is either a valid RKX token or a valid CCA token.

TABLE 25 Step number and brief summary Detailed description The process_source_key routine 1200 Verify that the source key is either a valid RKX token or a valid CCA token. If valid, the key is decrypted. If an output key variant exists, it is exclusive-OR'ed with the cleartext source key. 1202 - Does the If the source_key_identifier contains a NULL token, source key exist? defined as a token whose first byte is set to 0x00; or if the source_key_identifier is NULL, then abort the operation with an error. Else, proceed to step 1206. 1206 - Is source key If the source key token type is external and the version an RKX token? number is 0x10 indicating an RKX token, proceed to step 1214. Else proceed to step 1208. 1214 - Verify This description is written to accommodate either a source source key length that is an RKX token or a source key that is a CCA token, and trusted block and is implemented as a subroutine in the preferred Rule section CV embodiment. Length. A. Verify that the source key length is not larger than the CV Length in the Rule section's Common Export Key Parameters subsection. In the event that the CV Length is zero, the source key length will not be compared to the CV Length. B. If the CV Length is single (meaning 8 bytes in length), and the source key length is double (meaning 16 bytes in length), abort the operation with an error. C. If the source key is contained within an RKX token, a source key length of triple length (meaning 24 bytes) and a nonzero CV is considered an error since a triple length key is not compatible with control vectors which are designed for single and double length keys; however, if the CV Length in the Common Export Key Parameters subsection is zero or if the CV length is nonzero but the CV value is all binary zeroes, then the source key length restriction is waived. D. Verify that the length of the source key is greater than or equal to the Export Key Minimum Length in the Common Export Key Parameters subsection. E. Verify that the length of the source key is less than or equal to the Export Key Maximum Length in the Common Export Key Parameters subsection. F. Verify that the length of the source key is less than or equal to the Output Key Variant Length in the Common Export Key Parameters subsection provided that the Output Key Variant Length is nonzero (if the Output Key Variant Length is zero, then this comparison step is not performed). G. If the CV Length in the Common Export Key Parameters subsection is greater than the source key length, then this would imply that the CV Length is 16 and the source key length is 8 bytes. (Note that the possible CV Lengths are 0, 8, or 16; while the possible source key lengths are 8, 16, or 24 bytes). Therefore, in this case, the source key may be replicated (meaning that the 8-byte value is replicated to 16 bytes such that there are 2 equal halves), if the CV value in the Common Export Key Parameters subsection permits the replication and furthermore if the replication does not exceed the Export Key Maximum Length in the Common Export Key Parameters subsection. H. If the Rule section Symmetric Encrypted Output Key Format flag is set for CCA token output, and if the CV Length in the Common Export Key Parameters subsection is set to zero, then preserve the source key's CV value for the case of the source key being a CCA token. If the source key is an RKX token, the issue is moot since there is no CV contained in the token to be preserved. I. Various combinations of source key length, Common Export Key Parameter CV Length, and Common Export key Parameter CV value are examined for validity. 1) If the Common Export Key Parameters subsection contains a CV Length that is neither zero, single length, nor double length, then abort the operation with an error. 2) If the CV Length is set to single or double, the source key is single length, and the Common Export Key Parameters subsection contains a CV value that is set to binary zeroes, proceed to step 1228. 3) If the CV Length is double, the source key is double length, and the Common Export Key Parameters subsection contains a CV value that is set to binary zeroes, proceed to step 1228. 4) If the source key length is triple, the CV Length is double, and the Common Export Key Parameters subsection contains a CV value that is set to binary zeroes, proceed to step 1228. 5) If the source key length is triple, the CV Length is double, and the Common Export Key Parameters subsection contains a CV value that is nonzero, then abort the operation with an error. 6) If the source key length is triple and the CV Length is single, then abort the operation with an error. 7) If the CV Length is single, but the Common Export Key Parameters subsection contains a CV value that indicates that the key to which this CV is to be associated with must be double, then abort the operation with an error. 8) If the CV Length is double, the source key length is double, and the Common Export Key Parameters subsection contains a CV value that has a nonzero left half, but the CV left half indicates that the key to which this CV is to be associated with must be single, then abort the operation with an error. 9) If the CV Length is double, the source key length is double, and the Common Export Key Parameters subsection contains a CV value that has a nonzero left half, the CV left half indicates that the key to which this CV is to be associated with must be double, but the CV value has a binary zero right half, then abort the operation with an error. 10) If the CV Length is double, the source key length is double, and the Common Export Key Parameters subsection contains a CV value that has a nonzero left half, the CV left half indicates that the key to which this CV is to associated with must be double, the CV value has a nonzero right half, but the left half of the CV does not indicate that the CV is a left half or the right half of the CV does not indicate that the CV is a right half, then abort the operation with an error. 11) If the CV Length is double, the source key length is double, and the Common Export Key Parameters subsection contains a CV value that has a nonzero left half, the CV left half indicates that the key to which this CV is to associated with must be double, the CV value has a nonzero right half, the left half of the CV indicates that the CV is a left half, and the right half of the CV indicates that the CV is a right half, then perform the validity checks on the CV in the Common Export Key Parameters subsection such that the CV bits conform to control vector standards as documented in the CCA Basic Services Reference and Guide Appendix C: CCA control-vector definitions and key encryption. If there is a validity check failure, abort the operation with an error. 12) If the CV Length is single and the source key length is double, then abort the operation with an error. IF the CV Length is double, the source key length is single, the left half of the CV value in the Common Export Key Parameters subsection contains a nonzero value and its value indicates that the key to be associated with this CV must be single length, then perform the validity checks on the CV in the Common Export Key Parameters subsection such that the CV bits conform to control vector standards as documented in the CCA Basic Services Reference and Guide Appendix C: CCA control-vector definitions and key encryption. If there is a validity check failure, abort the operation with an error. 13) If the CV Length is double, the source key length is single, the left half of the CV value in the Common Export Key Parameters subsection contains a nonzero value, the right half of the CV value in the Common Export Key Parameters subsection contains a nonzero value, the left half of the CV indicates that the CV is a left half, and the right half of the CV indicates that the CV is a right half, then perform the validity checks on the CV in the Common Export Key Parameters subsection such that the CV bits conform to control vector standards as documented in the CCA Basic Services Reference and Guide Appendix C: CCA control- vector definitions and key encryption. If there is a validity check failure, abort the operation with an error. 14) If the CV Length is double, the source key length is single, the left half of the CV value in the Common Export Key Parameters subsection contains a nonzero value, the right half of the CV value in the Common Export Key Parameters subsection contains a nonzero value, the left half of the CV indicates that the CV is a left half, and the right half of the CV fails validity checks, then perform the validity checks on the left half of the CV in the Common Export Key Parameters subsection such that the CV bits conform to control vector standards. If there is a validity check failure, abort the operation with an error. Since the key is single length, a bad value for the CV right half is ignored. 1222 - Decrypt the A. Verify that the RKX token's key length field is set source key in the equal to the sum of either the confounder length and a RKX token. single length key, the confounder and a double length key, or the confounder and a triple length key. B. If the RKX token's key length field is set equal to the sum of the confounder length and a single length key, abort the operation with an error because a transporter key must not be single length in the preferred embodiment. C. Using the trusted block's Protection Information section's cleartext MAC key exclusive-OR'ed with the MAC key variant from FIG. 8, step 806, compute the ISO-16609 cipher-block chaining mode triple DES MAC over the RKX token starting at offset 0 up to but not including offset 56 in Table 18. D. Compare computed MAC against RKX token MAC value at offset 56 of Table 18. If unequal, abort the operation with an error. Else, decrypt the RKX token's confounder and key using the trusted block's Protection Information section's cleartext Mac key exclusive-OR'ed with the MAC key variant from FIG. 8, step 806. E. Verify that the trusted block's Source Key Rule Reference subsection's rule ID matches the source key RKX token's rule ID at offset 40 of Table 18. If unequal, abort the operation with an error. F. Determine whether source key replication is needed. If the input key length is single, the CV Length in the Common Export Key Parameters subsection is double length, the Rule section's Symmetric Encrypted Output key Format flag is set to CCA token format output, the left and right halves of the CV value in the Common Export Key Parameters subsection contain key-form bits indicating that the key to which this CV is to be associated with, has left and right halves that are not identical, then verify that the user's role has access control permissions enabled which would allow the replication of the single length source key to become a 16 byte (double length) key with the first 8 bytes equal to the second 8 bytes. G. Generate a warning message if the resultant key does not have odd parity, but continue to use the key. Do not abort the operation. H. Proceed to step 1228. 1208 - Is the source If the source key is an external CCA DES token, proceed key an external to step 1212. Else proceed to step 1210. CCA token? 1212 - Verify If the importer_key_identifier contains a NULL token, importer key defined as a token whose first byte is set to 0x00; or if the validity, importer_key_identifier is NULL, then abort the operation with an error. 1216 - Verify source Follow the procedure outlined in step 1214 of this figure. key length and trusted block Rule section CV Length. 1220 - Verify A. If the trusted block's rule section selected in FIG. 6, source key label step 612, contains an Export Key CCA Token template, and verify Parameters subsection that has a nonzero Source Key permission of Label Template Length, and the source_key_identifier external CCA token was not a key label, abort the operation with an error. export. B. If the external CCA token's CV bit referred to as the “export OK” bit 17 is equal to binary zero, abort the operation with an error. 1224 - Decrypt the A. Verify that the external CCA token contains a valid source key within TVV (token validation value), version number, and the external CCA token fields. token. B. If the version number of the external token is 1, verify that the source key's CV contains binary zeroes and furthermore verify that the source key's length is either double or triple. A single length source key with a version number set to 1 will result in an error and the operation will be aborted. C. Verify that the importer key does not have a zero CV value. If so, abort the operation with an error. D. Verify that the importer key does not have equal halves (i.e. the left and right 8 byte quantities are not equal). If so, abort operation with an error. E. Triple decrypt each 8-byte section of the source key using the importer key from FIG. 11, step 1114. If the CV Length in the Common Export Key Parameters subsection is greater than the source key length, then this would imply that the CV Length is 16 and the source key length is 8 bytes. (Note that the possible CV Lengths are 0, 8, or 16; while the possible source key lengths are 8, 16, or 24 bytes). Therefore, in this case, the source key may be replicated (meaning that the 8-byte value is replicated to 16 bytes such that there are 2 equal halves), if the CV value in the Common Export Key Parameters subsection permits the replication and furthermore if the replication does not exceed the Export Key Maximum Length in the Common Export Key Parameters subsection. F. Generate a warning message if the source key does not have odd parity, but continue to use the key. Do not abort the operation. G. Proceed to step 1228. 1210. Is the source If the source key is an internal CCA DES token, proceed to key an internal step 1218. Otherwise abort the operation with an error. CCA token? 1218. Verify source A. If the trusted block's rule section selected in FIG. 6, key label template, step 612, contains an Export Key CCA Token and verify Parameters subsection that has a nonzero Source Key permission of Label Template Length, and the source_key_identifier internal CCA token Was not a key label, abort the operation with an error. export. B. If the trusted block's rule section selected in FIG. 6, step 612, contains an Export Key CCA Token Parameters subsection that has a nonzero Source Key Label Template Length, and the source_key_identifier was a key label, indicating that the source key resides in a key storage repository: 1) Verify that the Source Key Label Template Length is 64 bytes, 2) Verify that the first character in the template is not be between 0x00-0x1F, nor can it be 0xFF; 3) Verify that the first character in the template is not numeric, 0x30-0x39; verify that the label in the template is terminated by a space on the right and that the remainder of the 64 byte field is padded with space characters (0x20); 4) Verify that the only special characters which may occur in the label template are 0x23 (#), 0x24 ($), 0x2E (.), and 0x40 (@); 5) Verify that the wildcard 0x2A (*) is permitted as the first character, the last character, or only character; 6) Verify that once a space is encountered, every character to the right of that space character, up to the 64 byte length, must be spaces as well; 7) Verify that only alphanumeric characters are present in the label template: a-z, A-Z, 0-9, and the 4 special characters, #, $, ., and @. 8) Once the key label template has been verified for validity, compare the template with the source key label. If a miscompare results, abort the operation with an error. C. If the external CCA token's CV bit referred to as the “export OK” bit 17 is equal to binary zero, abort the operation with an error. 1226 - Decrypt the A. Verify that the CCA token has a nonzero CV. Perform source key within the validity checks on the CV in this token such that the internal CCA the CV bits conform to control vector standards as token. documented in the CCA Basic Services Reference and Guide Appendix C: CCA control-vector definitions and key encryption. B. Verify the validity of the token validation value contained within the CCA token. C. Verify source key length and trusted block Rule section CV Length by following the procedure outlined in step 1214. D. Verify that the source key is a double length key, or a triple length key having a binary zero value for its CV. Using the source key token's MKVP, determine whether to use the current or old DES master key to decrypt the source key. Decrypt the source DES key under the corresponding DES master key using the source key token's CV according to the CCA Basic Services Guide and Reference Appendix C. E. If the CV Length in the Common Export Key Parameters subsection is greater than the source key length, then this would imply that the CV Length is 16 and the source key length is 8 bytes. (Note that the possible CV Lengths are 0, 8, or 16; while the possible source key lengths are 8, 16, or 24 bytes). Therefore, in this case, the source key may be replicated (meaning that the 8-byte value is replicated to 16 bytes such that there are 2 equal halves), if the CV value in the Common Export Key Parameters subsection permits the replication and furthermore if the replication does not exceed the Export Key Maximum Length in the Common Export Key Parameters subsection. F. Generate a warning message if the resultant key does not have odd parity, but continue to use the key. Do not abort the operation. 1228 - Return to caller.

FIG. 13 (verifyCertParms( )) together with table 26 highlight the major steps involved in the process of verifying the validity of the certificate parameter length field, as well as, the lengths contained within the certificate parameters table.

TABLE 26 Step number and brief summary Detailed description The verifyCertParms( ) routine 1300 verifies the validity of the certificate parms length field as well as the validity of the lengths contained within the certificate parms table. 1302 - Verify that the certificate_length input parameter is not Is certificate greater than some predefined maximum value. If so, abort too large? operation with an error. Else, proceed to step 1304. 1304 - If the rule section chosen in FIG. 6, step 612, specifies Asymmetric asymmetric encrypted output, proceed to step 1306. Else, output proceed to step 1318. desired? 1306 - Verify that the certificate_length is not zero. If zero, abort Certificate operation with an error. Else proceed to step 4. length zero? 1308 - Verify that the certificate_parms input parameter is Certificate present and that the certificat_parms_length is large parms enough to accommodate all the elements that are present? needed; A. The offset of the public key modulus within the certificate, B. The length of the public key modulus, C. The offset of the public key exponent within the certificate, D. The length of the public key exponent, E. The offset of the digital signature within the certificate, F. The length of the digital signature, G. The identifier for the hash algorithm used, H. The identifier for the digital signature hash formatting method, I. The offset of the block of data within the certificate that is to be hashed to compute the digital signature, and J. The length of the certificate data hashed to compute the digital signature. If the certificate_parms parameter is not present, or does not meet the aforementioned requirements, abort the operation with an error (1316). Else proceed to step 1310. 1310 - Verify the public key section within the trusted block Trusted exists. If not, abort operation with an error. Else, proceed block public to step 1312. key present? 1312 - Verify that neither Certificate A. The certificate parms modulus length, nor parms B. The certificate parms exponent length, nor lengths C. The certificate parms signature length, nor valid? D. The certificate parms data-to-hashed length is zero. If any of these lengths are zero, abort operation with an error (1318). Else proceed to step 1314. 1314 - A. Verify that the sum of the modulus offset and the Verify the modulus length does not exceed the length of the validity certificate; of the B. Verify that the sum of the exponent offset and the certificate exponent length does not exceed the length of the parameters certificate; C. Verify that the sum of the signature offset and signature length does not exceed the length of the certificate; D. Verify that the sum of the offset of the block of data within the certificate that is to be hashed and the length of this block does not exceed the length of the certificate. E. Verify that the modulus value within the certificate, pointed to by the modulus offset in the certificate parms, is not all binary zeroes. F. Verify that the exponent value within the certificate, pointed to by the exponent offset in the certificate parms, is not all binary zeroes. G. Verify that the certificates signature size, which may be less than the value of the signature length field but padded on the left with zero bits, is less than or equal to the size in bytes of the trusted block's public key modulus. If the certificate signature size is exactly equal to the size of the trusted block's public key modules, then compare the values of the certificate signature and trusted block public key modulus to verify that the value of the signature is less than the value of the modulus. H. Using the certificate parms offsets and lengths for modulus, exponent, and signature; verify that the modulus, exponent, and signature do not overlap each other. I. Verify that the public key modulus bit length in the certificate, pointed to by the certificate parms public key modulus offset, does not exceed the maximum allowable size set within the cryptographic adapter. 1318 - Return to caller

FIG. 14 (rkx_generate( )) 1400 together with table 27 provide the major steps involved in the process of building an RKX token data structure.

TABLE 27 Step number and brief summary Detailed description 1402 - Construct Build an RKX token data structure consisting of the an RKX token data following parts: an external key token type 0x02 and structure version number 0x10 per Table 18; the rule ID retrieved from the rule section selected in FIG. 6 step 612; the sum of the Generated Key Length in bytes retrieved from the rule section selected in FIG. 6 step 612 and the length of a confounder (8 bytes); an 8 byte random number for the confounder; and either an 8, 16, or 24 byte random number for the key. 1404 - Does an output If the Common Export Key Parameter subsection of the rule key variant exist? section selected by the rule ID input parameter in FIG. 6, step 612, exists and furthermore contains an output key variant, then proceed to step 1406. Else proceed to step 1408. 1406 - Apply the Exclusive-or the variant contained in the Common Export output key variant Key Parameter subsection of the rule section selected by the rule ID input parameter in FIG. 6, step 612, with the generated random number key portion. If the output key variant length is greater than the generated key length, then the leftmost bytes of the variant are used, up to key length. If the output key variant length is less than the length of the generated key portion, then abort the operation with an error. 1408 - Encrypt An ISO-16609 triple DES Cipher Block Chaining Mode confounder and encryption of the confounder prepended to the random key key portion (after the output key variant is applied per step 1406 of this figure if the output key variant was present, or after step 1402 of this figure if the output key variant is not present) is performed using an initial vector set to zero. 1410 - Compute Compute the ISO-16609 triple DES Cipher Block Chaining MAC over RKX Mode MAC over the RKX token between offsets 0 and 55 token inclusive, and place the 8-byte MAC value into the RKX token at offset 56. 1412 - Key check If the rule section selected by the rule ID in FIG. 6, step required? 612, indicates that a key check is to be performed, proceed to step 1414 in this figure. Else, proceed to step 1416 in this figure. 1414 - Perform a If the key check algorithm identifier in the rule section key check selected by the rule ID in FIG. 6, step 612, indicates that an encryption of 8 bytes of zeroes is to be performed with the cleartext key from step 1402 of this figure, then execute the following actions: A. If the generated key is single length, then output only 3 bytes of the resultant encryption in FIG. 6, step 646, if the input key_check_length parameter value was set to 3; B. Otherwise if the input key_check_length parameter value was set to a value between 4 and 8 inclusive, output only 4 bytes in FIG. 6, step 646. An input key_check_length parameter value of 0, 1, or 2 will result in an error due to insufficient length to hold the result, and the operation will be aborted. C. If the generated key is double or triple length, then output the full 8 bytes of the resultant encryption in FIG. 6, step 646, provided that the input key_check_length parameter value is set to 8. Otherwise, abort the operation with an error due to insufficient length to hold the result. If the key check algorithm identifier in the rule section selected by the rule ID in FIG. 6, step 612, indicates that an MDC-2 hash of the cleartext key from step 1 is to be performed, then a) Odd-parity adjust each byte of the cleartext key and b) Execute the MDC2 hash algorithm on the odd-parity adjusted key without the use of padding. Return the 16- byte value in FIG. 6, step 646, provided that the input key_check_length parameter is set to 16. A length less than 16 will result in an error and the operation will be aborted. 1416 - Produce Using the trusted block rule section selected from FIG. 6, asymmetric step 612, determine whether asymmetric encrypted output encrypted output? is to be produced. If not, proceed to step 1420. Else, proceed to step 1418. 1418 - Encrypt the Determine from the rule section selected from FIG. 6, generated key with step 612, whether PKCS1.2 output or RSA-OAEP output the public key format is desired. contained in the A. If RSA-OAEP output is specified in the rule section, certificate then format the generated key from step 1402 if no output key variant was used, or format the result of the generated key exclusive-OR'ed with the output key variant from step 1406, into an OAEP encryption block according to the method described in the RSA DSI PKCS#1-v2.0 documentation for RSAES-OAEP. B. If PKCS1.2 output was specified in the rule section, then format the generated key from step 1402 if no output key variant was used, or format the result of the generated key exclusive-OR'ed with the output key variant from step 1406, into a PKCS 1.2 encryption block according to the method described in the RSA DSI PKICS #1 documentation for block type 2. In the RSA PKCS #1 v2.0 standard, RSA terminology describes this as the RSAES-PKCS1-v1_5 format. 1420 - Return to caller

FIG. 15 (rkx_export( )) 1500 together with table 28 highlight the major steps involved in the process of exporting an RKX token.

TABLE 28 Step number and brief summary Detailed description 1502 - Retrieve Extract the key and key length out of the source key token cleartext source key that has been recovered into cleartext form in FIG. 12. 1504 - Key check If the rule section selected by the rule ID in FIG. 6, step required? 612, indicates that a key check is to be performed, proceed to step 1506 in this figure. Else, proceed to step 1508 in this figure. 1506 - Perform a key If the key check algorithm identifier in the rule section check selected by the rule ID in FIG. 6, step 612, indicates that an encryption of 8 bytes of zeroes is to be performed with the cleartext key from step 1502 of this figure, then execute the following actions: A. If the source key is single length, then output only 3 bytes of the resultant encryption in FIG. 6, step 646, if the input key_check_length parameter value was set to 3; B. Otherwise if the input key_check_length parameter value was set to a value between 4 and 8 inclusive, output only 4 bytes in FIG. 6, step 646. An input key_check_length parameter value of 0, 1, or 2 will result in an error due to insufficient length to hold the result, and the operation will be aborted. C. If the source key is double or triple length, then output the full 8 bytes of the resultant encryption in FIG. 6, step 646, provided that the input key_check_length parameter value is set to 8. Otherwise, abort the operation with an error due to insufficient length to hold the result. If the key check algorithm identifier in the rule section selected by the rule ID in FIG. 6, step 612, indicates that an MDC-2 hash of the cleartext key from step 1502 is to be performed, then a) Odd-parity adjust each byte of the cleartext key and b) Execute the MDC2 hash algorithm on the odd-parity adjusted key without the use of padding, per the MDC-2 description in the CCA Basic Services Guide and Reference; Appendix 10. Return the 16-byte value in FIG. 6, step 646, provided that the input key_check_length parameter is set to 16. A length less than 16 will result in an error and the operation will be aborted. 1508 - Does an If the Common Export Key Parameter subsection of the output key variant rule section selected by the rule ID input parameter in exist? FIG. 6, step 612, contains an output key variant, then proceed to step 1510. Else proceed to step 1512. 1510 - Apply the Exclusive-or the variant contained in the Common Export output key variant Key Parameter subsection of the rule section selected by the rule ID input parameter in FIG. 6, step 612, with the cleartext source key from step 1502 of this figure. If the output key variant length is greater than the source key length, then the leftmost bytes of the variant are used, up to key length. If the output key variant length is less than the length of the source key, then abort the operation with an error. 1512 - Create an If the rule section of the trusted block selected by the rule RKX token for the ID input parameter in FIG. 6, step 612, indicates that symmetric encrypted the symmetric encrypted output key format should be an output key? RKX token, proceed to step 1516. Else, proceed to step 1514. 1516 - Build an RKX Build an RKX token data structure consisting of the token following parts: A. An external key token type 0x02 and version number 0x10 per Table 18; B. The rule ID retrieved from the rule section selected in FIG. 6 step 612; C. The sum of the key length in bytes retrieved from the source key token in step 1502 of this figure and the length of a confounder (8 bytes); D. An 8 byte random number for the confounder; E. And either an 8, 16, or 24 byte value that is either: 1) The result of the exclusive-or operation between the cleartext source key from step 1502 and the output key variant from step 1510, or 2) The cleartext source key alone, from step 1502, in the event that no output key variant is present. 1520 - Encrypt An ISO-16609 triple DES Cipher Block Chaining Mode confounder and key encryption of the confounder and key portion built in step 1516, is performed using an initial vector set to zero. 1524 - Compute Compute the ISO-16609 triple DES Cipher Block MAC over RKX Chaining Mode MAC over the RKX token between token offsets 0 and 55 inclusive, and place the 8-byte MAC value into the RKX token at offset 56. Proceed to step 1522. 1514 - Encrypt key Perform validity checks on the source key using the value to be exported with of the control vector (CV) in the Common Export Key the transport key Parameters subsection of the rule section selected in FIG. 6, step 612, and the source key's 8-byte, 16-byte, or 24 byte value as follows: A. If the CV Length in the Common Export Key Parameters subsection is 8 bytes and if the source key is 16 bytes in length, abort the operation with an error; B. if the CV Length in the Common Export Key Parameters subsection is 16 bytes and if the source key is 16 bytes in length, and the CV contained in the Common Export Key Parameters subsection indicates that the source key should be a single length key, then abort the operation with an error; C. if the CV Length in the Common Export Key Parameters subsection is 16 bytes and if the source key is 16 bytes in length with the two halves being equal, and the CV contained in the Common Export Key Parameters subsection indicates that the source key should have unique halves, then abort the operation with an error; D. if the source key is triple length with all parts being unique, then the CV Length in the Common Export Key Parameters subsection must be either 0 or 16 bytes. In the latter case the CV contained in the Common Export Key Parameters subsection must contain binary zeroes, otherwise the operation is aborted with an error. Obtain the transporter key length and key parts from FIG. 10. 1) If the transporter key is contained in an RKX token, its length must be either double or triple. A single length transporter key will result in an error and the operation will be aborted. 2) If the transporter key is contained in a CCA token, its length must be double. A single or triple length transporter key from a CCA token will result in an error and the operation will be aborted. Perform EDE encryption on each 8-byte quantity of the source key according to the EDE multiple encipherment procedure using a CV as specified in the CCA Basic services Guide and Reference: Appendix C. i. The CV which will be used may be either the CV located in the Common Export Key Parameters subsection of the trusted block; ii. or if the CV Length contained in the Common Export Key Parameters subsection is 0, then the source key's CV will be used. iii. If the source key's CV is to be used, and if the source key is an RKX token which by definition does not contain a CV, then the CV value to be used will be 16 bytes of binary zeroes. iv. If the source key's CV is to be used, and if the source key is a CCA token of single length, then the preferred embodiment does not allow a CV of zero value to be used. A source key of single length and zero value CV is checked for in FIG. 12, step 1224 part B, as well as in FIG. 12, step 1226 part A. Two methods of EDE multiple encipherment will be allowed depending upon the value of the CV:  Method 1: The CV to be used is not all binary zeroes.  In this case, the source key can be either single or  double length. A triple length source key may be  exported with a CV containing all binary zeroes, but  cannot be exported with a CV that is nonzero. When  the CV to be used contains a nonzero value, the  preferred embodiment requires that the transporter key  be double length; however, it is possible that in future  revisions of the invention, a triple length transporter  key may be allowed. If the source key is either single  or double length:   then the left half of the CV is exclusive-OR'ed   with the transporter key's left half, making Key1   and Key3;   and the left half of the CV is exclusive-OR'ed with   the transporter key's right half, making Key2.  If the source key is double length:   then the right half of the CV is exclusive-OR'ed   with the transporter key's left half, making Key4   and Key6;   and the right half of the CV is exclusive-OR'ed   with the transporter key's right half, making Key5.  If the source key is single length, then the EDE  multiple encipherment procedure is performed on the  source key with Key1, Key2, and Key3. If  the source key is double length; then an EDE  multiple encipherment procedure is performed on the  source key's left half with Key1, Key2, and Key3; and  an EDE multiple encipherment procedure is  performed on the source key's right half with Key4,  Key5, and Key6.  Method 2: The CV to be used is all binary zeroes. In  this case, the source key can be double length or triple  length, not single. The transporter key may be either  double length if contained in an RKX token or CCA  token, or triple length if contained in an RKX token. If  the source key is double length and the transporter key  is double length:   The transport key's left half will be used as Key1,   Key3, Key4, and Key6.   The transport key's right half will be used as Key2   and Key5.   The EDE multiple encipherment procedure is   performed on the source key's left half with Key1,   Key2, and Key3.   The EDE multiple encipherment procedure is   performed on the source key's right half with   Key4, Key5, and Key6.  If the source key is triple length and the transporter  key is double length:   The transporter key's left half will be used as   Key1, Key3, Key4, and Key6.   The transporter key's right half will be used as   Key2 and Key5.   The EDE multiple encipherment procedure is   performed on the source key's first third with   Key1, Key2, and Key3.   The EDE multiple encipherment procedure is   performed on the source key's middle third with   Key4, Key5, and Key6.   The EDE multiple encipherment procedure is   performed on the source key's last third with Key1,   Key2, and Key3.  If the source key is double length and the transport  key is triple length:   The transport key's first third will be used as Key1   and Key4.   The transport key's middle third will be used as   Key2 and Key5.   The transport key's last third will be used as Key3   and Key6.   The EDE multiple encipherment procedure is   performed on the source key's left half with Key1,   Key2, and Key3.   The EDE multiple encipherment procedure is   performed on the source key's right half with   Key4, Key5, and Key6.  If the source key is triple length and the transporter  key is triple length:   The transport key's first third will be used as Key1   and Key4.   The transport key's middle third will be used as   Key2 and Key5.   The transport key's last third will be used as Key3   and Key6.   The EDE multiple encipherment procedure is   performed on the source key's first third with   Key1, Key2, and Key3.   The EDE multiple encipherment procedure is   performed on the source key's middle third with   Key4, Key5, and Key6.   The EDE multiple encipherment procedure is   performed on the source key's last third with Key1,   Key2, and Key3. 1518 - Build the Build an external CCA token. CCA external key A. Set the CCA token's version number to 0. token B. If the source key being exported is either double or triple length and the Common Export Key Parameters subsection of the Rule section selected in FIG. 6, step 612, contains a CV Length of 16 bytes and the CV value in this section is equal to 16 bytes of binary zeroes, then set the external token's version number to 1. C. If the source key being exported is either double of triple length and the Common Export Key Parameters subsection of the Rule section selected in FIG. 6, step 612, contains a CV Length of 0 and the CV value in the source key is equal to 16 bytes of binary zeroes (or if the source key was an RKX token), then set the external token's version number to 1. D. Copy the CV contained in the Common Export Keys Parameters subsection to the CCA token's CV field if the CV Length in this subsection is nonzero; otherwise copy the CV contained in the source key to the CCA token's CV field. E. Calculate the Token Validation Value (TVV) and place it into the CCA token. 1522 - Produce Using the trusted block rule section selected from FIG. asymmetric 6, step 612, determine whether asymmetric encrypted encrypted output? output is to be produced. If not, proceed to step 1528. Else, proceed to step 1526. 1526 - Encrypt the Determine from the rule section selected from FIG. 6, key to be exported step 612, whether PKCS1.2 output or RSA-OAEP output with the public key format is desired. contained in the A. If RSA-OAEP output is specified in the rule section, certificate then format the source key from step 5021 if no output key variant was used, or format the result of the source key exclusive-OR'ed with the output key variant from step 1510, into an OAEP encryption block according to the method described in the RSA DSI PKCS#1-v2.0 documentation for RSAES-OAEP. B. If PKCS1.2 output was specified in the rule section, then format the source key from step 1502 if no output key variant was used, or format the result of the source key exclusive-OR'ed with the output key variant from step 1510, into a PKCS 1.2 encryption block according to the method described in the RSA DSI PKCS #1 documentation for block type 2. In the RSA PKCS #1 v2.0 standard, RSA terminology describes this as the RSAES-PKCS1-v1_5 format. 1528 - Return to caller.

The following example of RKX usage takes the previously defined functions and illustrates how the function might be combined in an application to distribute a key to a remote device such as an ATM and keep a copy for local use. Some of the terminology used reflects typical terms used in ATM networks. The example illustrates a fairly complex real-world key distribution scenario, in which the following values are produced.

-   -   TMK (Terminal Master Key)—which is the root KEK used by the ATM         to exchange other keys. The TMK is produced in two forms:         encrypted under the ATM public key, so it can be sent to the         ATM, and as an RKX token that will be used in subsequent calls         to the RKX verb to produce other keys.     -   Key-encrypting key KEK1—that is encrypted under the TMK in a         form that can be understood by the ATM.     -   PIN-encrypting key PINKEY—that will be used by the ATM to         encrypt customer-entered PINs, and by the zSeries host to verify         those PINs. The PINKEY is produced in two forms: encrypted under         KEK1 in a form that can be understood by the ATM, and as a CCA         internal key token with the proper PIN key control vector,         encrypted under the CCA DES master key and suitable for use with         the zSeries CEX2C coprocessor.

It takes seven steps to produce these keys using the RKX service. These steps use a combination of four rules that would be contained in a single trusted block. The rules are referred to as GENERATE1, GENERATE2, EXPORT1, EXPORT2, and EXPORT3.

The GENERATE1 Rule section includes the following information:

-   -   Rule ID set to ASCII “GENERAT1”     -   Flag indicating that a new key is to be generated with length of         16 bytes     -   Flag indicating that the new key is to be symmetrically         encrypted in RKX token format     -   Flag indicating that the new key is to be also asymmetrically         encrypted in PKCS 1.2 output format     -   An output key variant which will be exclusive OR'ed with the         cleartext value of the generated key

The GENERATE2 Rule section includes the following information:

-   -   Rule ID set to ASCII “GENERAT2”     -   Flag indicating that a new key is to be generated with length of         16 bytes     -   Flag indicating that the new key is to be symmetrically         encrypted in RKX token format     -   Flag indicating that the new key is not to be asymmetrically         encrypted.     -   An output key variant which will be exclusive OR'ed with the         cleartext value of the generated key

The EXPORT1 Rule section includes the following information:

-   -   Rule ID set to ASCII “EXPORT1”     -   Flag indicating that an existing source key is to be exported     -   Flag indicating that the exported key is to be symmetrically         encrypted in CCA token format     -   Flag indicating that the new key is not to be asymmetrically         encrypted.     -   Exported key length must be between 8 and 16 bytes in length     -   No output key variant     -   No transport key variant     -   The rule ID that must have been used to create the transport key         is “GENERAT1”     -   The rule ID that must have been used to create the source key is         “GENERAT2”

The EXPORT2 Rule section includes the following information:

-   -   Rule ID set to ASCII “EXPORT2”     -   Flag indicating that an existing source key is to be exported     -   Flag indicating that the exported key is to be symmetrically         encrypted in CCA token format     -   Flag indicating that the new key is not to be asymmetrically         encrypted.     -   Exported key length must be between 8 and 16 bytes in length     -   No output key variant     -   No transport key variant     -   The rule ID that must have been used to create the transport key         is “GENERAT2”     -   The rule ID that must have been used to create the source key is         “GENERAT2”

The EXPORT3 Rule section includes the following information:

-   -   Rule ID set to ASCII “EXPORT3”     -   Flag indicating that an existing source key is to be exported     -   Flag indicating that the exported key is to be symmetrically         encrypted in CCA token format     -   Flag indicating that the new key is not to be asymmetrically         encrypted.     -   Exported key length must be between 8 and 16 bytes in length     -   No output key variant     -   No transport key variant     -   A PINVER control vector to be applied to the cleartext transport         key     -   The rule ID that must have been used to create the source key is         “GENERAT2”     -   No rule ID present for the transport key, indicating that the         transport key must be in CCA token format

-   1. Use RKX with rule GENERATE1 to generate a TMK for use with the     ATM. The key will be output in two forms.     -   e_(Pu)(TMK): Encrypted under the ATM public key, supplied in the         certificate parameter, CERT.     -   RKX(TMK): As an RKX token, suitable for subsequent input to the         RKX function.

-   2. Use RKX with rule GENERATE2 to generate a key-encrypting key KEK1     as an RKX token, RKX(KEK1).

-   3. Use RKX with rule GENERATE2 to generate a PIN key PINKEY as an     RKX token: RKX(PINKEY). Page: 131     -   (Note that the RKX(KEK1) and the RKX(PINKEY) are not equivalent         even though these keys were both generated using the GENERAT2         rule. The keys are different by virtue of the fact that the RKX         service generates keys with a random number generator.)

-   4. Use RKX with rule EXPORT1 to export KEK1 encrypted under the TMK     as a CCA token using a variant of zeroes applied to the TMK. This     produces e_(TMK)(KEK1).

-   5. Use RKX with rule EXPORT2 to export PINKEY encrypted under KEK1     as a CCA token using a variant of zeroes applied to KEK1. This     produces e_(KEK1)(PINKEY).

-   6. Use RKX with rule EXPORT3 to export PINKEY under KEK2, an     existing CCA key-encrypting key on the local zSeries server. This     produces e_(KEK2)(PINKEY), with the CCA control vector for a PIN     key.

-   7. Use the Key Import (KIM) function to import the PINKEY produced     in step 6 into the local system as an operational key. This produces     e_(MK)(PINKEY), a copy of the key encrypted under the local DES     master key (MK) and ready for use by CCA PIN API functions.

The Digital Signature Verify service (DSV) is used to verify a digital signature by providing the digital signature, the public key, the hash formatting method, and the hash of the data to be validated. Digital signatures may be verified using public keys that are contained in trusted blocks regardless of whether the trusted block also contains rules to govern its use when generating or exporting keys with the RKX verb (API).

A keyword named “TPK-ONLY”, when provided as an input parameter to the DSV service, blocks the use of regular CCA RSA key tokens and only permit the use of public keys contained in trusted blocks to execute the digital signature verification. If the keyword TPK-ONLY (Trusted Public Key only) is present, the DSV service will abort with an error if the public key supplied in the PKA_public_key_identifier parameter is not a trusted block containing a trusted public key. This allows an application to have assurance that a sensitive signature verification operation can be limited to operation with trusted public keys.

Table 29 summarizes application programming interface used to carry out digital signature verification.

TABLE 29 rule_array_count Input Integer rule_array Input String PKA_public_key_identifier_length Input Integer PKA_public_key_identifier Input String hash_length Input Integer Hash Input String signature_field_length Input Integer signature_field Input String

The elements of table 29 are as follows:

rule_array_count

-   -   The rule_array_count parameter is a pointer to an integer         variable containing the number of elements in the rule_array         variable. The value must be zero, one, or two is a pointer to an         integer variable containing the for this verb.         rule_array     -   The rule_array parameter is a pointer to a string variable         containing an array of keywords. The keywords are eight bytes in         length, and must be left justified and padded on the right with         space characters.

Keyword Meaning Digital signature hash formatting method (one, optional, for RSA) X9.31 Format the hash according to the ANSI X9.31 standard and compare to the digital signature. PKCS-1.1 Format the hash as specified in the RSA Data Security, Inc., Public Key Cryptography Standards #1 block type 01 and compare to the digital signature. The RSA PKCS #1 standard refers to this as RSASSA-PKCS-v1_5 when you BER encode the hash as described under the second note to the hash parameter. ISO-9796 Format the hash according to the ISO 9796-1 standard and compare to the digital signature. PKCS-1.0 Format the hash as specified in the RSA Data Security, Inc., Public Key Cryptography Standards #1 block type 00 and compare to the digital signature. ZERO-PAD The supplied hash value is placed in the low-order bit positions of a bit-string of the same length as the modulus with all non-hash-value bit positions set to zero. After ciphering the supplied digital signature, the result is compared to the hash-extended bit string. PKA public key token type (optional) TPK-ONLY The PKA_public_key_identifier must be a trusted block that contains two sections: (1) Trusted Block Information section which is required for all trusted blocks, and (2) Trusted Public Key section which contains the trusted public key and usage rules that indicate whether or not the trusted public key can be used in digital signature operations. Notes: (1) The hash for PKCS-1.1 and PKCS-1.0 should have been created using MD5 or SHA-1 algorithms. (2) The hash for ISO-9796 and ZERO-PAD can be obtained by any hashing method. PKA_public_key_identifier_length

-   -   The PKA_public_key_identifier_length parameter is a pointer to         an integer variable containing the number of bytes of data in         the PKA_public_key_identifier variable.         PKA_public_key_identifier     -   The PKA_public_key_identifier parameter is a pointer to a string         variable containing either a key label identifying a key-storage         record of a registered public-key, a key label identifying a         key-storage record of a Trusted Block, an RSA key token, or an         internal Trusted Block key token.         hash_length     -   The hash_length parameter is a pointer to an integer variable         containing the number of bytes of data in the hash variable.         hash     -   The hash parameter is a pointer to a string variable containing         the hash information to be verified.     -   Notes:     -   1. For ISO-9796, the information identified by the hash         parameter must be less than or equal to one-half of the number         of bytes required to contain the modulus of the RSA key.         Although ISO 9796-1 allows messages of arbitrary bit length up         to one-half of the modulus length, this verb requires the input         text to be a byte multiple up to the correct maximum length.     -   2. For PKCS-1.0 or PKCS-1.1, the information identified by the         hash parameter must be 11 bytes shorter than the number of bytes         required to contain the modulus of the RSA key, and should be         the ASN.1 BER encoding of the hash value. You can create the BER         encoding of an MD5 or SHA-1 value by prepending these strings to         the 16-byte or 20-byte hash values, respectively: For MD5;         X′3020300C 06082A86 4886F70D 02050500 0410′         -   For SHA-1; X′30213009 06052B0E 03021A05 000414′     -   3. For ZERO-PAD, the information identified by the hash         parameter must be less than or equal to the number of bytes         required to contain the modulus of the RSA key.         signature_field_length     -   The signature_field length parameter is a pointer to an integer         variable containing the number of bytes of data in the         signature_field variable.         signature_field     -   The signature_field parameter is a pointer to a string variable         containing the digital signature. The digital signature         bit-field is in the low-order bits of the byte string containing         the digital signature.

FIG. 16 (DSV Service—main( )) 1600 together with Table 30 highlight the major steps involved in the digital signature verification process.

TABLE 30 Step number and brief summary Detailed description 1600 - Keyword If the input keyword parameter is set to “TPK-ONLY”, proceed to step set to “TPK- 1604. Else, proceed to step 1620. ONLY”? 1604 - Validate the See FIG. 7 - validate_block( ) for details. Verify that all these trusted block conditions are met: E. No unknown sections have been built into the trusted block, F. The trusted block token identifier is internal, G. The Active flag is enabled, H. Fields within the trusted block have valid lengths and valid values. If these conditions are not met, abort operation with an error (1618). 1606 - Recover See FIG. 8 - decrypt_tb_mac_key( ) for details. trusted block MAC D. Decrypt the confounder and MAC key located in the Protection key Information section of the trusted block under a variant of the PKA Master Key and using an IV of binary zeroes. E. The variant is the following hexadecimal string where each byte has even parity so that the parity of the XOR result of the PKA master key with the variant is not altered: C9 2E BB 35 D2 AA 56 D8 - 9C 66 E4 12 2B E7 A0 A3 - B4 55 FF E4 D7 E7 F6 41. F. Decryption is performed using triple DES CBC mode. 1608 - Compute See FIG. 9 - compute_tb_mac( ) for details. MAC value over D. Copy the trusted block to some temporary_block. the trusted block E. Fill in the following Protection Information section fields of the temporary block with binary zeroes: encrypted MAC key, ISO- 16609 TDES CBC MAC value, MKVP (master key verification pattern). F. Compute an ISO-16609 CBC mode TDES MAC over the entire temporary block contents using the recovered TDES MAC key and an IV of binary zeroes. 1610 - Computed The computed MAC from step 1608 is compared to the MAC value MAC = stored contained in the trusted block Protection Information section. trusted block C. If equal, proceed to step 1612, MAC? D. Else, abort operation with an error. 1612 - Verify the This routine obtains the MDC4 hash of the current PKA master key and MKVP in the compares the result to the MKVP contained in the Protection Information trusted block section of the trusted block. If a mismatch occurs, the MDC4 hash of the old PKA master key is obtained and compared to the MKVP contained in the Protection Information section of the trusted block. If a mismatch still occurs, abort the operation with an error (1618). 1614 - Does trusted If the trusted block does not contain a Trusted public Key section, abort block contain a the operation with an error. Else, proceed to step 1616. Trusted Public Key

The flow charts/diagrams depicted herein are just examples. There may be many variations to these charts/diagrams or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention.

As described above, the embodiments of the invention may be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. Embodiments of the invention may also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other non-transitory computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a non-transitory storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.

While the preferred embodiment to the invention has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described. 

1. A data structure stored on a non-transitory computer readable storage medium, the data structure comprising instructions that are cryptographically protected against alteration or misuse, wherein said instructions further comprise a trusted block that defines specific key management policies that are permitted when applications employ said trusted block to generate, import, or export symmetric cryptographic keys, and wherein said applications comprise: application programming interfaces (API); embedded firmware; operating system code; and hardware configured operations; and wherein said applications further comprise: a Trusted_Block_Create (TBC) function; a Remote_Key_Export (RKX) function; and wherein said TBC function creates said trusted block; and wherein said RKX function uses said Trusted Block to generate, import or export symmetric keys according to a set of parameters in said Trusted Block; and wherein said RKX function creates a RKX token; and wherein said RKX token encases said keys; and wherein said trusted block has a field containing rules that provide an ability to limit how said trusted block is used, thereby reducing the risk of said trusted block being employed in unintended ways or with unintended keys; and wherein said rules are created and approved by a cryptographic module under the control of at least two separate individuals; wherein said trusted block is created with integrity protection by a message authentication code (MAC); and wherein said MAC is calculated over the contents of said trusted block; and wherein said trusted block comprises a randomly generated MAC key that is used to achieve said trusted blocks integrity protection; and wherein said MAC key and a prepended confounder is encrypted under a variant of said cryptographic modules master key.
 2. The data structure according to claim 1, wherein said rules are protected and bound to said trusted block; and wherein said rule comprises at least one of the following: an indictor of whether said rule is to be used to generate, import, or export said symmetric cryptographic keys; and an indicator of whether said generated, said imported, or said exported symmetric cryptographic keys should be in the form of a key that is immediately usable, or in the form of said RKX token that can only be used as a subsequent input to another RKX function call; or an indicator of whether the said generated or said exported symmetric cryptographic key should be encrypted under a public key contained in a vendor-supplied certificate.
 3. The data structure according to claim 1, wherein said rules may comprise a rule ID, which is a value that identifies said rule and where said rule should be used; and wherein said rules can reference other rules by referring to said rule ID.
 4. The data structure according to claim 1, wherein said rule may comprise at least one of the following: a transport key rule reference to identify what rule must have been used previously to produce a key used as a transport key input to said RKX function; or a source key rule reference to identify what rule must have been used previously to produce a key used as a source key input to said RKX function; or an importer key rule reference to identify what rule must have been used previously to produce a key used an importer key input to said RKX function.
 5. The data structure according to claim 1, wherein said rule may comprise at least one of the following: information that controls the length of the keys that can be generated with said rule; or information controlling the length of keys that can be exported with said rule; or information controlling the length of keys that can be imported with said rule.
 6. The data structure according to claim 1, wherein said rule comprises a plurality of variants; and wherein a first variant can be exclusive-or'ed (XORed) with the cleartext value of an output key exported by said trusted block prior to said output key being enciphered by a transport key; and wherein a second variant can be XORed with a transport key prior to said transport key being employed to encrypt said output key that is exported or generated by said trusted block; and wherein a third variant out can be exclusive-or'ed (XORed) with the cleartext value of an input source key imported by said trusted block prior to said output key being enciphered by said cryptographic modules master key.
 7. The data structure according to claim 1, wherein said rule comprises a plurality key label templates; and wherein said templates specify acceptable key label values for either keys that are to be exported by said trusted block, or importer keys that are to be used for decrypting keys that are to be imported by said trusted block; and wherein host-applied labels are compared to said template; and wherein said key will not be exported if said host-applied label does not correspond to said key label values specified by said template.
 8. The data structure according to claim 1, wherein said keys have structure; and wherein said key structure further comprises a token, and wherein said token is a data structure used to encase said key; and wherein said token further comprises control vectors; and wherein said rules comprise information to control which of said keys can be exported, based on said control vectors associated with said keys; and wherein said control vectors have values; and wherein said rule information allows the acceptable control vectors to be specified so that sets of related control vector values are acceptable, while values outside said set are rejected.
 9. The data structure according to claim 1, further comprising activation and expiration date information; and wherein said RKX function enforces said activation and expiration date information before carrying out said instructions in said trusted block.
 10. The data structure according to claim 1, wherein said rule comprises a plurality of masks of control vector bits; and wherein said rule comprises the required values of said control vector bits; and wherein said masks of control vector bits and said required values are enforced by said RKX function when exporting a key or using an importer key; and wherein said rule may comprise a control vector that is applied to a cryptographic module's master key, before said master key is being employed to encrypt an output key that is imported by said trusted block.
 11. The data structure according to claim 1, wherein said trusted block has a cryptographic public key; and wherein said TBC function creates and approves said cryptographic public key with said cryptographic module under the control of at least two separate individuals.
 12. The data structure according to claim 1, wherein said RKX token further comprises a confounder used to initialize an encryption-block chaining value during the encryption of said encased key; and wherein said confounder and said encased key within said RKX token are encrypted using the same MAC key that was used to protect said trusted block.
 13. The data structure according to claim 1, wherein said RKX token further comprises a rule identification field that specifies a particular rule section that was used to create said RKX token.
 14. The data structure according to claim 13, wherein said RKX token further comprises a MAC value; and wherein said MAC value is computed over said RKX token; and wherein said RKX token further comprises: an encrypted confounder; a key value; and wherein said rule identification field has a value; and wherein said rule identification field value can be compared with instructions within said rule sections of said trusted block, to determine whether said key within said RKX token may be used as either an importer key-key encrypting key, a source key, or exporter key-encrypting key.
 15. A computer-implemented method for securely transferring symmetric cryptographic keys to other devices, wherein said method utilizes a data structure comprising instructions that are cryptographically protected against alteration or misuse, wherein said instructions further comprise a trusted block that defines specific key management policies that are permitted when applications employ said trusted block to generate, import, or export said symmetric cryptographic keys, and wherein said applications comprise: application programming interfaces (API); embedded firmware; operating system code; and hardware configured operations; and wherein said applications further comprise: a Trusted_Block_Create (TBC) function; a Remote_Key_Export (RKX) function; wherein said TBC function creates said trusted block; and wherein said RKX function uses said Trusted Block to generate, import, or export symmetric keys according to a set of parameters in said Trusted Block; and wherein said trusted block has a field containing rules that provide an ability to limit how said trusted block is used, thereby reducing the risk of said trusted block being employed in unintended ways or with unintended keys; and wherein said method comprises: at least two separate individuals cooperating to create said trusted block under multiple control.
 16. The method according to claim 15, wherein said trusted block has a data structure comprising: zero or one trusted public key section, zero or more rule sections, zero or one trusted block label section, one trusted block information section, and zero or one application defined data section.
 17. The method according to claim 15, wherein said trusted block is protected by a MAC that is computed over the contents of said data structure; and wherein said trusted block contains a public key and optional rules to control export of other keys associated with said other device(s) that use that public key; and wherein for remote key distribution, said public key will be the root certification key for the other device, and said public key will be used to verify the signature on public key certificates for individual devices; and wherein it is also possible for the Trusted Block to be used simply as a trusted public key container, in which case said public key in said trusted block will be used in functions such as Digital Signature Verify.
 18. The method according to claim 15, wherein said rules in said trusted block further comprise a function to generate, import, or export said symmetric cryptographic keys; and wherein said function to generate, import, or export said symmetric cryptographic keys is said RKX function; and wherein said RKX function creates a RKX token; and wherein said RKX token holds said encrypted symmetric keys so as to bind them to said trusted block, and allows sequences of RKX calls to be bound together as if they are an atomic operation.
 19. The method according to claim 15, wherein said RKX function provides for secure transport of said symmetric keys from a security module to another device.
 20. A non-transitory storage medium encoded with machine-readable computer code for a processor to implement an instruction set of instructions designed to securely transfer symmetric cryptographic keys to other devices; and wherein said instructions are cryptographically protected against alteration or misuse; and wherein said instructions further comprise a trusted block that defines specific key management policies that are permitted when applications employ said trusted block to generate, import, or export said symmetric cryptographic keys, and wherein said applications comprise: application programming interfaces (API); embedded firmware; operating system code; and hardware configured operations; and wherein said applications further comprise: a Trusted_Block_Create (TBC) function; a Remote_Key_Export (RKX) function; wherein said TBC function creates said trusted block; and wherein said RKX function uses said Trusted Block to generate, import, or export symmetric keys according to a set of parameters in said Trusted Block; and wherein said trusted block has a field containing rules that provide an ability to limit how said trusted block is used, thereby reducing the risk of said trusted block being employed in unintended ways or with unintended keys. 